Einar Uggerud

• Platania, Elena; Caruso, Francesco; Nevin, Austin; Vila, Anna; Buti, David & Uggerud, Einar (2025). Transformations of Late Medieval Church Art: The Role and Challenges of Conservation Science. I Streeton, Noëlle Lynn Wenger; Frøysaker, Tine & Bjerregaard, Peter (Red.), Sacred Medieval Objects and Their Afterlives in Scandinavia. De Gruyter Brill. ISSN 9789004707573. s. 321–358. doi: 10.1163/9789004712034_011. Fulltekst i vitenarkiv Vis sammendrag

  Interconnected investigations between conservators, historians, heritage scientists and museum professionals centre on objects that were essential to medieval Christianity in Scandinavia (c. 1100‒1530). Through new and diverse physical data from polychrome sculptures, shrines, winged altarpieces and painted banners, the authors probe a range of issues and problems, from original devotional functions and changing appearances, to the impacts of changing liturgies, locations and priorities. This book highlights the diversity of theoretical and practical approaches to sacred medieval religious objects, and brings together new findings related to the transformations of these objects since the Reformations.

• Løyland, Sverre & Uggerud, Einar (2024). Competing Reaction Pathways in Gas-Phase Oxidation of C<inf>6</inf>H<inf>6</inf> by Protonated H<inf>2</inf>O<inf>2</inf>. Journal of Physical Chemistry A. ISSN 1089-5639. 128(49), s. 10465–10473. doi: 10.1021/acs.jpca.4c03722. Fulltekst i vitenarkiv Vis sammendrag

  Reactions between protonated hydrogen peroxide and benzene (and benzene-d6) have been studied in the gas phase using an FT-ICR mass spectrometer. Four competing paths for the bimolecular system were identified, namely, proton transfer, hydride abstraction, dissociative single-electron transfer, and an electrophilic addition of HO+ to give the Wheland intermediate [C6H6, OH]+ followed by a subsequent elimination of water. The three latter pathways correspond to three different ways to oxidize benzene. All reaction mechanisms have been modeled using quantum chemical methods, and the calculations are in agreement with the experimental observations. The total reaction rate proceeds at collision rate (slightly higher than the calculated Langevin capture rate), which exemplifies the high reactivity of H3O2+ toward arenes. These observations demonstrate a much richer chemical landscape than previously inferred from the corresponding condensed phase reaction, where only electrophilic substitution by solvated HO+ was described.

• Gjermestad, Christian Sant; Ryding, Mauritz Johan Olof & Uggerud, Einar (2023). Gas phase models of hydride transfer from divalent alkaline earth metals to CO<inf>2</inf> and CH<inf>2</inf>O. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 2023(25), s. 16065–16076. doi: 10.1039/d2cp05964a. Fulltekst i vitenarkiv Vis sammendrag

  The reactivity of HMg+, HMgCl, and HMgCl2− in hydride transfer reactions with CO2 and CH2O were studied by means of the reverse reactions—decarboxylation of HCO2MgCln+/0/− and deformylation of CH3OMgCln+/0/− (n = 0–2)—by a combination of quantum chemical computations and mass spectrometry experiments. HCO2Mg+, HCO2MgCl and HCO2MgCl2− display similar energetics for unimolecular carbon dioxide loss; for CH3OMg+, CH3OMgCl and CH3OMgCl2−, formaldehyde loss is more favourable for the cationic species than for the anionic one, with the neutral species found in-between. Despite very similar overall thermochemistry for each of the charge states of the CO2 and CH2O systems, the intermediate reaction barriers are higher for the CO2 eliminations due to a more complex and demanding reaction mechanism. Exothermic ligand exchange is observed for CH3OMg+ reacting with CO2, forming HCO2Mg+ and CH2O. Both the thermochemistry and the presence of intermediate energy barriers slightly disfavour this type of ligand exchange for CH3OMgCl and CH3OMgCl2−. It was also found that CH3OMg+ reacts readily with H2O to eliminate H2, whereas quantum chemical computations predict that the corresponding neutral and anionic species suffer unfavourable reaction thermochemistry. A corresponding reaction for the magnesium formate compounds was not observed. Quantum chemical computations were performed to investigate periodic trends in reactivity. The energetic requirements for decarboxylation of HCO2M+, HCO2MCl and HCO2MCl2− increase in the order M = Be, Mg, Ca, Sr and Ba; the only exception is the cationic Be species for which the reaction is more endothermic than for the corresponding Mg species. For deformylation of CH3OM+, CH3OMCl and CH3OMCl2− the trends are more irregular and less pronounced than for the decarboxylation reactions; however, the Be species was found to have higher reaction energies than the Mg species for all the methoxy-compounds irrespective of charge state. The effect on decarboxylation and deformylation upon replacing Cl with F, Br or I was found to be minimal for all aforementioned species. The consequences of these observations on the reverse reactions, hydride transfer to CO2 and CH2O, are discussed, and the effects of systematic structural changes on reactivity are rationalized on the basis of thermochemical cycles and well-known periodic trends.

• Qureishy, Thomas; Løyland, Sverre; Jørgensen, Susanne Jøntvedt; Færgestad, Eline Mosleth; Norby, Truls & Uggerud, Einar (2022). Mechanisms for sonochemical oxidation of nitrogen. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 24(25), s. 15357–15364. doi: 10.1039/d2cp01995g. Fulltekst i vitenarkiv Vis sammendrag

  N2O, and mixtures of N2 and O2, dissolved in water—both in the presence and absence of added noble gases—have been subjected to ultrasonication with quantification of nitrite and nitrate products. Significant increase in product formation upon adding noble gas for both reactant systems is observed, with the reactivity order Ne < Ar < Kr < Xe. These observations lend support to the idea that extraordinarily high electronic and vibrational temperatures arise under these conditions. This is based on recent observations of sonoluminescence in the presence of noble gases and is inconsistent with the classical picture of adiabatic bubble collapse upon acoustic cavitation. The reaction mechanisms of the first few reaction steps necessary for the critical formation of NO are discussed, illustrated by quantum chemical calculations. The role of intermediate N2O in this series of elementary steps is also discussed to better understand the difference between the two reactant sources (N2O and 2 : 1 N2 : O2; same stoichiometry).

• Perrin, Charles L.; Agranat, Israel; Bagno, Alessandro; Braslavsky, Silvia E.; Fernandes, Pedro Alexandrino & Gal, Jean-François [Vis alle 18 forfattere av denne artikkelen] (2022). Glossary of terms used in physical organic chemistry (IUPAC Recommendations 2021). Pure and Applied Chemistry. ISSN 0033-4545. 94(4), s. 353–534. doi: 10.1515/pac-2018-1010. Fulltekst i vitenarkiv Vis sammendrag

  Abstract This Glossary contains definitions, explanatory notes, and sources for terms used in physical organic chemistry. Its aim is to provide guidance on the terminology of physical organic chemistry, with a view to achieving a consensus on the meaning and applicability of useful terms and the abandonment of unsatisfactory ones. Owing to the substantial progress in the field, this 2021 revision of the Glossary is much expanded relative to the previous edition, and it includes terms from cognate fields.

• Jestilä, Joakim Samuel & Uggerud, Einar (2021). Computational Exploration of the Direct Reduction of CO2 to CO Mediated by Alkali Metal and Alkaline Earth Metal Chloride Anions. Organometallics. ISSN 0276-7333. 40(11), s. 1735–1743. doi: 10.1021/acs.organomet.1c00213. Fulltekst i vitenarkiv Vis sammendrag

  We present a computational survey of the reduction of CO2 to CO by alkali metal and alkaline earth metal chloride anions in the gas phase, uncovering also mechanistic aspects on the selective tuning between oxalate and carbonate products relevant to chemical or electrochemical processes. The reduction of a single CO2 molecule is typically endothermic, whereas the corresponding disproportionation reaction involving two molecules is exothermic. Our computational results suggest consistent periodic trends with reaction energies being highest for elements toward the center of each group. The factors governing these trends are discussed, in particular, the covalent contributions to bonding in these highly ionic species.

• Jestilä, Joakim Samuel; Iker, Zsuzsanna; Ryding, Mauritz Johan Olof & Uggerud, Einar (2020). The unimolecular dissociation of magnesium chloride squarate (ClMgC4O4−) and reductive cyclooligomerisation of CO on magnesium. Organic and biomolecular chemistry. ISSN 1477-0520. 18(46), s. 9499–9510. doi: 10.1039/d0ob01994a. Fulltekst i vitenarkiv
• Jestilä, Joakim Samuel; Denton, Joanna K.; Perez, Evan H.; Khuu, Thien; Apra, Edoardo & Xantheas, Sotiris S. [Vis alle 8 forfattere av denne artikkelen] (2020). Characterization of the alkali metal oxalates (MC2O4−) and their formation by CO2 reduction via the alkali metal carbonites (MCO2−). Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 22(14), s. 7460–7473. doi: 10.1039/d0cp00547a. Fulltekst i vitenarkiv
• Platania, Elena; Streeton, Noëlle Lynn Wenger; Lluveras-Tenorio, Anna; Vila, Anna; Buti, David & Caruso, Francesco [Vis alle 10 forfattere av denne artikkelen] (2020). Identification of green pigments and binders in late medieval painted wings from Norwegian churches. Microchemical Journal. ISSN 0026-265X. 156. doi: 10.1016/j.microc.2020.104811. Fulltekst i vitenarkiv Vis sammendrag

  Green pigments in micro-samples taken from three late-medieval painted objects from Norwegian churches have been investigated with the aim to characterize their constituents and understand how they relate to damages observed in passages containing green paints. The cross-sections were analyzed by optical microscopy under visible and UV light, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectrometry and vibrational spectroscopies (Raman, ATR-FTIR). In addition, Gas Chromatography coupled with Mass Spectrometry was employed for the characterization of binding media, using a derivatization methodology recently developed for the detection of metal soaps in paint samples. This extensive characterization aided the identification of the individual constituents and the stratigraphy of green paints. It also builds the foundation for future ageing studies that can provide better insights into the mechanisms of the processes at stake in selective delamination of paints containing copper complexes.

• Uggerud, Einar (2020). INTERACTIONS AND ENERGY TRANSFER. Mass spectrometry reviews (Print). ISSN 0277-7037. doi: 10.1002/mas.21656. Fulltekst i vitenarkiv
• Jestilä, Joakim Samuel & Uggerud, Einar (2019). Unimolecular Dissociation of Hydrogen Squarate (HC4O4–) and the Squarate Radical Anion (C4O4•–) in the Gas Phase and the Relationship to CO Cyclooligomerization. Journal of Organic Chemistry. ISSN 0022-3263. 84(21), s. 14005–14014. doi: 10.1021/acs.joc.9b02185. Fulltekst i vitenarkiv
• Hansen, Klavs; Ryding, Mauritz Johan Olof & Uggerud, Einar (2019). Magic numbers and stabilities of heavy water clusters, (D2O)ND+, N = 3 −48. International Journal of Mass Spectrometry. ISSN 1387-3806. 440, s. 14–19. doi: 10.1016/j.ijms.2019.03.003. Fulltekst i vitenarkiv
• Lengyel, Jozef; Ryding, Mauritz Johan Olof; Myhre, Rolf Heilemann & Uggerud, Einar (2019). Reactions of microhydrated ozonide with methyl chloride. International Journal of Mass Spectrometry. ISSN 1387-3806. 435, s. 129–135. doi: 10.1016/j.ijms.2018.10.022. Fulltekst i vitenarkiv
• Platania, Elena; Streeton, Noëlle Lynn Wenger; Vila, Anna; Buti, David; Caruso, Francesco & Uggerud, Einar (2019). Investigation of mineralization products of lead soaps in a late medieval panel painting. Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy. ISSN 1386-1425. 228. doi: 10.1016/j.saa.2019.117844. Fulltekst i vitenarkiv Vis sammendrag

  Metal soaps pose significant concerns in the preservation of paintings made with oil as a binding medium. In highly alkaline environments, metal soap aggregates may undergo mineralization processes with the formation of new phases, such as carbonates, chlorides, oxides and sulfates of the metal cations that are present in pigments or paint additives. In this work, we report new examples of the mineralization of lead soaps in paint-cross sections taken from a late-medieval panel painting owned by the Museum of Cultural History at the University of Oslo. Scientific analyses were carried out with optical microscopy under UV and visible light, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and Raman spectroscopy to investigate and characterize the nature of the compounds present in the samples. Lead (II,IV) oxide, which is presumed to be a secondary product in the mineralization of lead soaps, has been identified in lead-based paint.

• Rebrov, O; Poline, M.; Ryding, Mauritz Johan Olof; Thomas, Richard D.; Uggerud, Einar & Larsson, Mats (2019). Non-covalently bonded diastereomeric adducts of amino acids and (S)-1-phenylethanol in low-energy dissociative collisions. Molecular Physics. ISSN 0026-8976. doi: 10.1080/00268976.2019.1615145. Fulltekst i vitenarkiv
• Miller, Glenn B. S. & Uggerud, Einar (2018). C−C Bond Formation of Mg‐ and Zn‐Activated Carbon Dioxide. Chemistry - A European Journal. ISSN 0947-6539. 24(18), s. 4710–4717. doi: 10.1002/chem.201706069. Fulltekst i vitenarkiv
• Blaziak, Kacper; Tzeli, Demeter; Xantheas, Sotiris S. & Uggerud, Einar (2018). The activation of carbon dioxide by first row transition metals (Sc–Zn). Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 20(39), s. 25495–25505. doi: 10.1039/c8cp04231d. Fulltekst i vitenarkiv
• Jestilä, Joakim Samuel & Uggerud, Einar (2018). Unimolecular dissociation of anions derived from succinic acid (H2Su) in the gas phase: HSu− and ClMgSu−. Relationship to CO2 fixation. European Journal of Mass Spectrometry. ISSN 1469-0667. 24(1), s. 33–42. doi: 10.1177/1469066717729904. Fulltekst i vitenarkiv Vis sammendrag

  Electrospray ionization of mixtures of succinic acid (here denoted H2Su) and magnesium chloride in water/methanol give rise to ions of the type ESu− (E = H or ClMg). The unimolecular dissociation of these ions was studied by collisionally induced dissociation mass spectrometry and interpreted by quantum chemical calculations (density functional theory and the composite Gaussian-4 method) of relevant parts of the potential energy surfaces. The major dissociation pathways from HSu− were seen to be dehydration and decarboxylation, while ClMgSu− mainly undergoes decarboxylation. The latter reaction proceeds without barrier for the reverse reaction; addition of CO2 to a Grignard type structure ClMg(CH2CH2CO2)–. In contrast, addition of CO2 to the analogous H(CH2CH2CO2)– ion has a substantial barrier. Dehydration of HSu− gives rise to deprotonated succinic anhydride via a transition state for the key intramolecular proton transfer having an entropically favorable seven-member ring structure. The succinate systems studied here are compared to the previously reported analogous maleate systems, providing further insight to the structure–reactivity relationship.

• Platania, Elena; Streeton, Noëlle Lynn Wenger; Kutzke, Hartmut; Karlsson, Arne; Uggerud, Einar & Andersen, Niels Højmark (2018). Infrared, Raman and Computational Study of a Crystalline Mononuclear Copper Complex of relevance to the Pigment Verdigris. Vibrational Spectroscopy. ISSN 0924-2031. 97, s. 66–74. doi: 10.1016/j.vibspec.2018.05.004. Fulltekst i vitenarkiv
• Miller, Glenn B. S. & Uggerud, Einar (2017). Dissociation of Mg(II) and Zn(II) complexes of simple 2-oxocarboxylates-relationship to CO2 fixation, and the Grignard and Barbier reactions. Organic and biomolecular chemistry. ISSN 1477-0520. 15(32), s. 6813–6825. doi: 10.1039/c7ob01327b. Fulltekst i vitenarkiv
• Kyluk, Kostiantyn; Rebrov, Oleksii; Ryding, Mauritz Johan Olof; Thomas, Richard D; Uggerud, Einar & Larsson, Mats (2017). Low-Energy Collisions of Protonated Enantiopure Amino Acids with Chiral Target Gases. Journal of the American Society for Mass Spectrometry. ISSN 1044-0305. 28(12), s. 2686–2691. doi: 10.1007/s13361-017-1796-7. Fulltekst i vitenarkiv
• Rebrov, Oleksii; Kulyk, Kostiantyn; Ryding, Mauritz Johan Olof; Thomas, Richard D; Uggerud, Einar & Larsson, Mats (2017). Chirally sensitive collision induced dissociation of proton-bound diastereomeric complexes of tryptophan and 2-butanol. Chirality. ISSN 0899-0042. 29(3-4), s. 115–119. doi: 10.1002/chir.22679. Fulltekst i vitenarkiv
• Burschowsky, Daniel; Krengel, Ute; Uggerud, Einar & Balcells, David (2017). Quantum chemical modeling of the reaction path of chorismate mutase based on the experimental substrate/product complex. FEBS Open Bio. 7(6), s. 789–797. doi: 10.1002/2211-5463.12224. Fulltekst i vitenarkiv Vis sammendrag

  Chorismate mutase is a well‐known model enzyme, catalyzing the Claisen rearrangement of chorismate to prephenate. Recent high‐resolution crystal structures along the reaction coordinate of this enzyme enabled computational analyses at unprecedented detail. Using quantum chemical simulations, we investigated how the catalytic reaction mechanism is affected by electrostatic and hydrogen‐bond interactions. Our calculations showed that the transition state (TS) was mainly stabilized electrostatically, with Arg90 playing the leading role. The effect was augmented by selective hydrogen‐bond formation to the TS in the wild‐type enzyme, facilitated by a small‐scale local induced fit. We further identified a previously underappreciated water molecule, which separates the negative charges during the reaction. The analysis includes the wild‐type enzyme and a non‐natural enzyme variant, where the catalytic arginine was replaced with an isosteric citrulline residue.

• Abu-Samha, Mahmoud; Ryding, Mauritz Johan Olof; Uggerud, Einar; Sæthre, Leif J & Børve, Knut J. (2017). Changing role of carrier gas in formation of ethanol clusters by adiabatic expansion. Journal of Chemical Physics. ISSN 0021-9606. 147(1). doi: 10.1063/1.4989475. Fulltekst i vitenarkiv
• Miller, Glenn B. S. & Uggerud, Einar (2017). The unimolecular dissociation of the glyoxylate, pyruvate, trifluoropyruvate, and α-oxobutyrate anions. Decarboxylation vs. decarbonylation of simple α-ketocarboxylates. International Journal of Mass Spectrometry. ISSN 1387-3806. 413, s. 150–162. doi: 10.1016/j.ijms.2016.05.002. Fulltekst i vitenarkiv
• Blaziak, Kacper; Miller, Glenn B. S.; Ryding, Mauritz Johan Olof & Uggerud, Einar (2017). Reaction Model for the Formation of Benzene from Benzoates and Grignard Reagents. European Journal of Organic Chemistry. ISSN 1434-193X. 2017, s. 4272–4276. doi: 10.1002/ejoc.201700816. Fulltekst i vitenarkiv
• Uggerud, Einar (2017). Chapter One - The Factors Determining Reactivity in Nucleophilic Substitution. Advances in Physical Organic Chemistry. ISSN 0065-3160. 51, s. 1–51. doi: 10.1016/bs.apoc.2017.07.001. Fulltekst i vitenarkiv
• Ryding, Mauritz Johan Olof; Fernández, Israel & Uggerud, Einar (2017). Reactions between microhydrated superoxide anions and formic acid. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 19(34), s. 23176–23186. doi: 10.1039/c7cp03820h. Fulltekst i vitenarkiv
• Ryding, Mauritz Johan Olof; Fernández, Israel & Uggerud, Einar (2016). Oxidation of NO• by small oxygen species HO2- and O2•-: The role of negative charge, electronic spin and water solvation. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 18(14), s. 9524–9536. doi: 10.1039/c6cp00290k. Fulltekst i vitenarkiv
• Ryding, Mauritz Johan Olof; Debnarova, Andrea; Fernández, Israel & Uggerud, Einar (2015). Nucleophilic Substitution in Reactions between Partially Hydrated Superoxide Anions and Alkyl Halides. Journal of Organic Chemistry. ISSN 0022-3263. 80(12), s. 6133–6142. doi: 10.1021/acs.joc.5b00651. Fulltekst i vitenarkiv
• Abboud, Jose-Luis M; Koppel, Ilmar A; Uggerud, Einar; Leito, Ivo; Koppel, Ivar & Sekiguchi, Osamu [Vis alle 10 forfattere av denne artikkelen] (2015). Solution and Gas-Phase Acidities of all-trans (all-E) Retinoic Acid: An Experimental and Computational Study. Chemistry - A European Journal. ISSN 0947-6539. 21(31), s. 11238–11243. doi: 10.1002/chem.201500717. Fulltekst i vitenarkiv
• Rebrov, O; Kulyk, K; Ryding, Mauritz Johan Olof; Stocket, M; Alexander, J & Zettergren, H [Vis alle 11 forfattere av denne artikkelen] (2015). Interactions of amino acid enantiomers with chiral target in high and low energy collisions. Journal of Physics: Conference Series (JPCS). ISSN 1742-6588. 635(3). doi: 10.1088/1742-6596/635/3/032053. Fulltekst i vitenarkiv
• Ryding, Mauritz Johan Olof; Izsak, Robert; Merlot, Patrick; Reine, Simen Sommerfelt; Helgaker, Trygve & Uggerud, Einar (2015). Geometry of the magic number H+(H2O)21 water cluster by proxy. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 17, s. 5466–5473. doi: 10.1039/C4CP05246C. Fulltekst i vitenarkiv
• Miller, Glenn B. S.; Fäseke, Vincent & Uggerud, Einar (2015). Unimolecular dissociation of anions derived from maleic acid (MaH2) in the gas phase: MaH- and MaMgCl- - relationship to Grignard chemistry and reductive CO2 fixation. European Journal of Mass Spectrometry. ISSN 1469-0667. 21(3), s. 545–556. doi: 10.1255/ejms.1325. Fulltekst i vitenarkiv
• Erichsen, Marius Westgård; Mortén, Magnus; Svelle, Stian; Sekiguchi, Osamu; Uggerud, Einar & Olsbye, Unni (2015). Conclusive Evidence for Two Unimolecular Pathways to Zeolite-Catalyzed De-alkylation of the Heptamethylbenzenium Cation. ChemCatChem. ISSN 1867-3880. 7(24), s. 4143–4147. doi: 10.1002/cctc.201500793. Fulltekst i vitenarkiv
• Miller, Glenn B.S.; Esser, Tim K.; Knorke, Harald; Gewinner, Sandy; Schöllkopf, Wieland & Heine, Nadja [Vis alle 8 forfattere av denne artikkelen] (2014). Spectroscopic Identification of a Bidentate Binding Motif in the Anionic Magnesium–CO2 Complex ([ClMgCO2]−). Angewandte Chemie International Edition. ISSN 1433-7851. 53(52), s. 14407–14410. doi: 10.1002/anie.201409444. Fulltekst i vitenarkiv
• Aasheim, Jens Harald; Fliegl, Heike; Uggerud, Einar; Bonge-Hansen, Tore & Eisenstein, Odile (2014). Stereoselectivity through a network of non-classical CH weak interactions: A prospective study of a bicyclic organocatalytic scaffold. New Journal of Chemistry. ISSN 1144-0546. 38(12), s. 5975–5982. doi: 10.1039/c4nj01460j. Fulltekst i vitenarkiv
• Ryding, Mauritz Johan Olof; Giuliani, Alexandre; Patanen, Minna; Niskanen, Johannes; Simoes, Grazieli & Miller, Glenn B.S. [Vis alle 13 forfattere av denne artikkelen] (2014). X-ray induced fragmentation of size-selected salt cluster-ions stored in an ion trap. RSC Advances. 4, s. 47743–47751. doi: 10.1039/c4ra09787d. Fulltekst i vitenarkiv
• Smalø, Hans Sverre; Rybkin, Vladimir; Klopper, Wim; Helgaker, Trygve & Uggerud, Einar (2014). Mechanochemistry: The effect of dynamics. Journal of Physical Chemistry A. ISSN 1089-5639. 118(36), s. 7683–7694. doi: 10.1021/jp504959z. Fulltekst i vitenarkiv
• Ryding, Mauritz Johan Olof & Uggerud, Einar (2014). CO&lt;sub&gt;2&lt;/sub&gt; incorporation in hydroxide and hydroperoxide containing water clusters - A unifying mechanism for hydrolysis and protolysis. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 16(20), s. 9371–9382. doi: 10.1039/c4cp00100a. Fulltekst i vitenarkiv
• Smalø, Hans Sverre & Uggerud, Einar (2013). Breaking covalent bonds using mechanical force, which bond breaks? Molecular Physics. ISSN 0026-8976. 111(9-11), s. 1563–1573. doi: 10.1080/00268976.2013.811554. Fulltekst i vitenarkiv
• Fernandez, Israel; Bickelhaupt, F. Matthias & Uggerud, Einar (2013). Reactivity in nucleophilic vinylic substitution (SNV): SNV pi versus SNV sigma mechanistic dichotomy. Journal of Organic Chemistry. ISSN 0022-3263. 78(17), s. 8574–8584. doi: 10.1021/jo401242f. Fulltekst i vitenarkiv
• Simakov, Anton; Miller, Glenn B.S.; Bunkan, Arne Joakim Coldevin; Hoffmann, Mark & Uggerud, Einar (2013). The dissociation of glycolate-astrochemical and prebiotic relevance. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 15(39), s. 16615–16625. doi: 10.1039/c3cp51638e. Fulltekst i vitenarkiv
• Rybkin, Vladimir; Simakov, Anton; Bakken, Vebjørn; Reine, Simen Sommerfelt; Kjærgaard, Thomas & Helgaker, Trygve [Vis alle 7 forfattere av denne artikkelen] (2013). Insights into the dynamics of evaporation and proton migration in protonated water clusters from large-scale bornoppenheimer direct dynamics. Journal of Computational Chemistry. ISSN 0192-8651. 34(7), s. 533–544. doi: 10.1002/jcc.23162. Fulltekst i vitenarkiv
• Sekiguchi, Osamu & Uggerud, Einar (2013). Fragmentation of Deprotonated Glycolaldehyde in the Gas Phase and Relevance to the Formose Reaction. Journal of Physical Chemistry A. ISSN 1089-5639. 117(44), s. 11293–11296. doi: 10.1021/jp4053715. Fulltekst i vitenarkiv
• Dossmann, Héloïse; Afonso, Carlos; Tabet, Jean-Claude & Uggerud, Einar (2013). Unimolecular dissociation characteristics of cationic complexes between nicotinic acid and Cu(II) and Ni(II). International Journal of Mass Spectrometry. ISSN 1387-3806. 354-355, s. 165–174. doi: 10.1016/j.ijms.2013.05.030. Fulltekst i vitenarkiv
• Ryding, Mauritz Johan Olof; Andersson, Patrik Urban; Zatula, Alexey & Uggerud, Einar (2012). Proton mobility in water clusters. European Journal of Mass Spectrometry. ISSN 1469-0667. 18(2), s. 215–222. doi: 10.1255/ejms.1172. Fulltekst i vitenarkiv
• Ryding, M.J.; Jonsson, Å.M.; Zatula, Alexey; Andersson, P.U. & Uggerud, Einar (2012). Reactions of H+(pyridine)(m)(H2O)(n) and H+(NH3)(1)(pyridine)(m)(H2O)(n) with NH3: experiments and kinetic modelling. Atmospheric Chemistry and Physics (ACP). ISSN 1680-7316. 12(6), s. 2809–2822. doi: 10.5194/acp-12-2809-2012. Fulltekst i vitenarkiv
• Dossmann, Héloïse; Afonso, Carlos; Lesage, Denis; Tabet, Jean-Claude & Uggerud, Einar (2012). Formation and Characterization of Gaseous Adducts of Carbon Dioxide to Magnesium, (CO2)MgX- (X=OH, Cl, Br). Angewandte Chemie International Edition. ISSN 1433-7851. 51(28), s. 6938–6941. doi: 10.1002/anie.201108477. Fulltekst i vitenarkiv
• Smalø, Hans Sverre & Uggerud, Einar (2012). Ring opening vs. direct bond scission of the chain in polymeric triazoles under the influence of an external force. Chemical Communications. ISSN 1359-7345. 48(84), s. 10443–10445. doi: 10.1039/c2cc34056a. Fulltekst i vitenarkiv
• Ryding, Mauritz Johan Olof; Ruusuvuori, Kai; Andersson, Patrik Urban; Zatula, Alexey; McGrath, Matthew J & Kurtén, Theo [Vis alle 9 forfattere av denne artikkelen] (2012). Structural Rearrangements and Magic Numbers in Reactions between Pyridine-Containing Water Clusters and Ammonia. Journal of Physical Chemistry A. ISSN 1089-5639. 116(20), s. 4902–4908. doi: 10.1021/jp3021326. Fulltekst i vitenarkiv
• Zatula, Alexy; Ryding, Mauritz Johan Olof; Andersson, Patrik Urban & Uggerud, Einar (2012). Proton mobility and stability of water clusters containing alkali metal ions. International Journal of Mass Spectrometry. ISSN 1387-3806. 330-332, s. 191–199. doi: 10.1016/j.ijms.2012.07.017. Fulltekst i vitenarkiv
• Zimnicka, Magdalena; Wilenska, Beata; Sekiguchi, Osamu; Uggerud, Einar & Danikiewicz, Witold (2012). Reactions of nitrophenide and halonitrophenide ions with acrylonitrile and alkyl acrylates in the gas phase: addition to the carbonyl group versus Michael addition. Journal of Mass Spectrometry. ISSN 1076-5174. 47(4), s. 425–438. doi: 10.1002/jms.2042. Fulltekst i vitenarkiv
• Zimnicka, Magdalena; Sekiguchi, Osamu; Uggerud, Einar & Danikiewicz, Witold (2012). Reactions of nitrophenide and halonitrophenide ions with acrylonitrile and alkyl acrylates in the gas phase: The case of [M-2](-) ion formation. International Journal of Mass Spectrometry. ISSN 1387-3806. 316-318, s. 76–83. doi: 10.1016/j.ijms.2011.12.015. Fulltekst i vitenarkiv
• Zatula, Alexey; Ryding, Mauritz Johan Olof & Uggerud, Einar (2012). Concerted proton migration along short hydrogen bonded water bridges in bipyridine-water clusters. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 14(40), s. 13907–13909. doi: 10.1039/c2cp42060k. Fulltekst i vitenarkiv
• Simakov, Anton; Sekiguchi, Osamu; Bunkan, Arne Joakim Coldevin & Uggerud, Einar (2011). Energetics and Mechanisms for the Unimolecular Dissociation of Protonated Trioses and Relationship to Proton-Mediated Formaldehyde Polymerization to Carbohydrates in Interstellar Environments. Journal of the American Chemical Society. ISSN 0002-7863. 133(51), s. 20816–20822. doi: 10.1021/ja206600w. Fulltekst i vitenarkiv
• Ryding, Mauritz; Zatula, Alexey; Andersson, Patrik & Uggerud, Einar (2011). Isotope exchange in reactions between D2O and size-selected ionic water clusters containing pyridine, H+(pyridine)(m)(H2O)(n). Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 13(4), s. 1356–1367. doi: 10.1039/c0cp00416b. Fulltekst i vitenarkiv
• Iozzi, Maria Francesca; Helgaker, Trygve & Uggerud, Einar (2011). Influence of External Force on Properties and Reactivity of Disulfide Bonds. Journal of Physical Chemistry A. ISSN 1089-5639. 115(11), s. 2308–2315. doi: 10.1021/jp109428g. Fulltekst i vitenarkiv
• Zatula, Alexey; Andersson, Patrik Urban; Ryding, Mauritz Johan Olof & Uggerud, Einar (2011). Proton mobility and stability of water clusters containing the bisulfate anion, HSO4-(H2O)(n). Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 13(29), s. 13287–13294. doi: 10.1039/c1cp21070j. Fulltekst i vitenarkiv
• Anichina, Janna; Krapp, Andreas; Uggerud, Einar & Bohme, Diethard K. (2011). Alkali cation regulation of the dissociation and hydrobromination of a deprotonated trideoxynucleotide. International Journal of Mass Spectrometry. ISSN 1387-3806. 304(2-3), s. 165–171. doi: 10.1016/j.ijms.2010.08.001. Fulltekst i vitenarkiv
• Hvelplund, Preben; Kurtén, Tage; Støchkel, K; Ryding, Mauritz; Nielsen, SB & Uggerud, Einar (2010). Stability and Structure of Protonated Clusters of Ammonia and Water, H+(NH3)(m) (H2O)(n). Journal of Physical Chemistry A. ISSN 1089-5639. 114(27), s. 7301–7310. doi: 10.1021/jp104162k. Fulltekst i vitenarkiv
• Fernandez, Israel; Frenking, Gernot & Uggerud, Einar (2010). Rate-Determining Factors in Nucleophilic Aromatic Substitution Reactions. Journal of Organic Chemistry. ISSN 0022-3263. 75(9), s. 2971–2980. doi: 10.1021/jo100195w. Fulltekst i vitenarkiv
• Andersson, Patrik; Öjekull, Jenny; Pettersson, Jan B. C.; Markovic, Nikola; Hellberg, Fredrik & Thomas, Richard D. [Vis alle 15 forfattere av denne artikkelen] (2010). Formation of Highly Rovibrationally Excited Ammonia from Dissociative Recombination of NH4+. The Journal of Physical Chemistry Letters. 1(17), s. 2519–2523. doi: 10.1021/jz100828u. Fulltekst i vitenarkiv
• Fooladi, Erik; Krapp, Andreas; Sekiguchi, Osamu; Tilset, Mats & Uggerud, Einar (2010). Mechanism for C-H bond activation in ethylene in the gas phase vs. in solution - vinylic or agostic? Revisiting the case of protonated Cp*Rh(C2H4)(2). Dalton Transactions. ISSN 1477-9226. 39(27), s. 6317–6326. doi: 10.1039/b926542b. Fulltekst i vitenarkiv Vis sammendrag

  When Cp*Rh(C2H4)2H+ (2) is exposed to C2H4 in the gas phase, inside the cell of an FT-ICR mass spectrometer, the most notable feature is the lack of any bimolecular reactivity. Collisional activation of 2 leads to ethylene loss and formation of Cp*Rh(C2H4-mju-H)+ (3). In contrast to the reactivity of 2 in solution, ethylene dimerisation is negligible in the gas phase. Coordinatively unsaturated 3, rather than 2, is the major species in which reactivity is observed to occur. Compound 3 reacts with ethylene in three parallel processes: (a) Slow addition of ethylene to give 2; (b) rapid, intermolecular hydrogen atom exchange (monitored in separate reactions with free C2D4 to give 3-d1-5); (c) ligand substitution of ethylene in 3. DFT calculations reproduce these observations, showing low barriers for hydrogen scrambling, high barrier to ligand loss in 2, and even higher barriers to elimination of either H2 or ethane. Mechanistic models for the elimination and scrambling processes are discussed.

• Hansen, K; Andersson, P.U. & Uggerud, Einar (2009). Activation energies for evaporation from protonated and deprotonated water clusters from mass spectra. Journal of Chemical Physics. ISSN 0021-9606. 131(12). doi: 10.1063/1.3230111. Fulltekst i vitenarkiv
• Rosenberg, Marianne Lenes; Aasheim, Jens Harald; Trebbin, M; Uggerud, Einar & Hansen, Tore (2009). Synthesis of a 1,3,4,5-tetrahydrobenzindole beta-ketoester. Tetrahedron Letters. ISSN 0040-4039. 50(47), s. 6506–6508. doi: 10.1016/j.tetlet.2009.09.032. Fulltekst i vitenarkiv
• Panja, Subhais; Hvelplund, Preben; Nielsen, Steen Brøndsted & Uggerud, Einar (2009). The reduction of water clusters H+(H2O)(n) to (OH-)(H2O)(m) by double electron transfer from Cs atoms. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 11(29), s. 6125–6131. doi: 10.1039/b903517f. Fulltekst i vitenarkiv
• Uggerud, Einar (2009). Steric and electronic effects in S(N)2 reactions. Pure and Applied Chemistry. ISSN 0033-4545. 81(4), s. 709–717. doi: 10.1351/PAC-CON-08-10-03. Fulltekst i vitenarkiv
• Sekiguchi, Osamu; Meyer, V; Letzel, MC; Kuck, D & Uggerud, Einar (2009). Energetics and reaction mechanisms for the competitive losses of H-2, CH4 and C2H4 from protonated methylbenzenes-implications to the methanol-to-hydrocarbons (MTH) process. European Journal of Mass Spectrometry. ISSN 1469-0667. 15(2), s. 167–181. doi: 10.1255/ejms.953. Fulltekst i vitenarkiv
• Hvelplunda, P; Nielsen, SB; Panjaa, S; Pedersen, JOP & Uggerud, Einar (2009). On the existence of the hypervalent H3O, H2DO, HD2O, and D3O radicals. International Journal of Mass Spectrometry. ISSN 1387-3806. 281(1-2), s. 52–54. doi: 10.1016/j.ijms.2008.12.004. Fulltekst i vitenarkiv
• Fernandez, I; Frenking, G & Uggerud, Einar (2009). The Interplay between Steric and Electronic Effects in S(N)2 Reactions. Chemistry - A European Journal. ISSN 0947-6539. 15(9), s. 2166–2175. doi: 10.1002/chem.200801833. Fulltekst i vitenarkiv
• Iozzi, Maria Francesca; Helgaker, Trygve & Uggerud, Einar (2009). Assessment of theoretical methods for the determination of the mechanochemical strength of covalent bonds. Molecular Physics. ISSN 0026-8976. 107(23-24), s. 2537–2546. doi: 10.1080/00268970903401041. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Løyland, Sverre & Uggerud, Einar (2023). Mechanistic insight into the industrial production of H₂O₂ using mass spectrometry. Fulltekst i vitenarkiv Vis sammendrag

  The anthraquinone process is an industrial, catalytic process for the production of hydrogen peroxide, H₂O₂, from hydrogen and oxygen gas. First, an anthraquinone, 1, is catalytically hydrogenated with palladium and hydrogen gas to form an anthrahydroquinone, 2. The reduced molecule 2 is subsequently oxidized back to 1 by spontaneous reaction with oxygen gas, and in the process forming H₂O₂. Although more than 4 million tons of H₂O₂ are produced yearly, the reaction mechanism for the formation of H₂O₂ from 2 is not understood in detail, and the mechanisms presented in most textbooks are probably wrong as they are spin-forbidden. We have performed reactions between a cationic derivative of 2 and O2 gas in the collision cell of a mass spectrometer in conjunction with quantum chemical computations to elucidate the mechanism. As the samples of 2 react with atmospheric oxygen in seconds, the experiments also present some challenging practical aspects of mass spectrometric analyses of reactive molecules.

• Roberts, Aubrey Jane; Görbitz, Carl Henrik; Mossige, Joachim; Samset, Bjørn Hallvard & Uggerud, Einar (2023). Abels Tårn. [Radio]. NRK P3 EKKO. Fulltekst i vitenarkiv
• Norby, Truls; Ma, Quanbao; Qureishy, Thomas & Uggerud, Einar (2022). Plasma-enhanced ammonia synthesis over nanoscopic Ru/CeO2. Fulltekst i vitenarkiv
• Jemterud, Torkild; Sverdrup-Thygeson, Anne; Uggerud, Einar; Einevoll, Gaute; Joner, Erik & Skogvoll, Vidar [Vis alle 7 forfattere av denne artikkelen] (2022). Abels tårn - Suicidale fluer og en ode til urin. Fulltekst i vitenarkiv
• Jestilä, Joakim Samuel & Uggerud, Einar (2021). An investigation of reductive CO2 activation using tandem mass spectrometric techniques. Fulltekst i vitenarkiv
• Tysse, Morten; Jensen, Vidar Remi; Børve, Knut J.; Eliasson, Sondre Hilmar Hopen & Uggerud, Einar (2021). Electrocatalytic Reduction of CO2 to CO by Iron and Zinc Porphyrin and Bacteriochlorin - A DFT study. Fulltekst i vitenarkiv
• Haugnes, Gunhild M.; Tallaksen, Lena M.; Vogt, Rolf David; Storelvmo, Trude; Hessen, Dag Olav & Stordal, Frode [Vis alle 9 forfattere av denne artikkelen] (2018). Klimaforskerne tar temperaturen på tropesommeren. [Journal]. Titan.uio.no. Fulltekst i vitenarkiv
• Burschowsky, Daniel; Krengel, Ute; Uggerud, Einar & Balcells, David (2015). Quantum chemical modeling of chorismate mutase catalysis. Fulltekst i vitenarkiv
• Gadmar, Tone Charlotte; Uggerud, Einar; Løvvik, Ole Martin & Jemterud, Torkild (2014). Abels Tårn. [Radio]. EKKO, NRK P2. Fulltekst i vitenarkiv
• Fernandez, Israel; Frenking, Gernot & Uggerud, Einar (2010). Comment on "The Interplay between Steric and Electronic Effects in S(N)2 Reactions" Response. Chemistry - A European Journal. ISSN 0947-6539. 16(19), s. 5542–5543. doi: 10.1002/chem.200903569. Fulltekst i vitenarkiv
• Uggerud, Einar & Gundersen, Lise-Lotte (2009). Nobelprisen i kjemi 2009. [Radio]. Verdt å vite, NRK P2. Fulltekst i vitenarkiv
• Ryding, Mauritz; Andersson, Patrik; Krapp, Andreas; Frenking, Gernot; Sekiguchi, Osamu & Bakken, Vebjørn [Vis alle 7 forfattere av denne artikkelen] (2008). Elementary chemical reactions of water clusters. Fulltekst i vitenarkiv
• Uggerud, Einar (2008). Structures and dynamics of protonated water clusters. Fulltekst i vitenarkiv
• Uggerud, Einar (2008). Dehydrogenation reactions studied in the gas phase. Fulltekst i vitenarkiv
• Uggerud, Einar (2008). Water clusters and one-electron reductions of solvated cations. Fulltekst i vitenarkiv
• Uggerud, Einar (2008). Dehydrogenation reactions studied in the gas phase. Fulltekst i vitenarkiv
• Uggerud, Einar (2008). Elementary Processes in Water Clusters. Fulltekst i vitenarkiv
• Uggerud, Einar (2008). Elementary Processes in Water Clusters. Fulltekst i vitenarkiv
• Uggerud, Einar (2008). The SN2 Reaction. Fulltekst i vitenarkiv
• Jestilä, Joakim Samuel; Uggerud, Einar & Helgaker, Trygve (2021). Reductive gas-phase ion chemistry of simple oxocarbons in the presence of alkali and alkaline earth metals. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  In a circular carbon economy, carbon dioxide (CO2) is recycled and used as a molecular building block to make fuels, chemicals and materials, driven by renewable energy sources. Hence, the molecule represents a potential replacement for oil, natural gas and coal as one of the primary sources of carbon. A major bottleneck stems from the fact that CO2 requires activation before it can be converted. This work explores the activation and reduction of CO2 by the alkali metal and alkaline earth metal chloride anions on a fundamental level. It sheds light on relevant factors in the conversion of CO2 to valuable products such as oxalate (C2O42−) and carbon monoxide (CO), as well as further conversion of the latter. The aforementioned processes proceed via metal-CO2 intermediates—chemical species formed during conversion of reactants to products—and this thesis links their properties to the extent of CO2 activation. Specifically, more complete electron transfer from the metal to CO2 and larger structural changes in the intermediates are associated with lower energetic demands for further reaction and conversion. These results could prove useful for the development of efficient CO2-recycling processes.

• Thoresen, Eirik Mydske; Shafir, Alexandr; Wärnmark, Kenneth & Uggerud, Einar (2018). Cyclometalated Ruthenium(II) Complexes and their Incorporation into the Metal-Organic Framework UiO-67 for Photocatalytic CO2 Reduction. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Two of the biggest challenges for the world today are the global warming, partly resulting from the increased CO2 emissions, and the need of new energy sources due to an increasing world population and the necessary replacement of fossil fuels. The capture and transformation of CO2 into high energy containing chemicals could contribute to both of these challenges. In this PhD thesis, a type of porous materials is developed and studied with the aim of such CO2 utilization. These materials are called metal-organic frameworks (MOFs) and can be readily functionalized by a wide range of chemical species. New, cyclometalated ruthenium(II) complexes were synthesized and incorporated into the MOF UiO-67 by different synthetic methods. These complexes and the corresponding functionalized MOFs were found to intensely absorb visible light. The MOFs were also tested for photocatalytic CO2 reduction, in which the reduction products carbon monoxide, methanol, and formic acid were observed.

• Miller, Glenn B. S.; Uggerud, Einar & Helgaker, Trygve (2018). Intrinsic Reactivity of Reduced Mg and Zn with CO2 – Relationships to Biological and Non-Biological C–C Bond Formation. Universitetet i Oslo. Fulltekst i vitenarkiv
• Gjermestad, Christian Sant & Uggerud, Einar (2018). Gas phase reactivity of methoxide and formate complexes of Mg(II). Hydride transfer and relationship to the water-gas shift reaction. Universitetet i Oslo. Fulltekst i vitenarkiv
• Otterstad, Marius Friberg & Uggerud, Einar (2017). Reactions between simple models of biomolecular compounds and small water clusters of the superoxide anion. Universitetet i Oslo. Fulltekst i vitenarkiv
• Jestilä, Joakim Samuel & Uggerud, Einar (2016). Unimolecular Dissociation of Succinate Anions in the Gas Phase and Relevance to Reductive Carbon Dioxide Fixation. Universitetet i Oslo. Fulltekst i vitenarkiv
• Bunkan, Arne Joakim Coldevin; Nielsen, Claus Jørgen; Uggerud, Einar & Helgaker, Trygve (2015). A theoretical and experimental study of atmospheric reactions of amines and their degradation products. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Amine-based CO2 capture has been proposed as a way of mitigating climate change. In this work, the fundamental processes governing the atmospheric gas phase chemistry of amines released from CO2 capture have been studiedusing computational and experimental methods. The reactions of amines, amides and imines with OH radicals have been studied with computational methods. The reactions are all characterized by strongly bound pre-reaction complexes and submerged barriers to hydrogen abstraction. Rate coefficients calculated from statistical rate theory show negative temperature dependencies and are in good agreement with experimental results where available. It has been suggested that the climate effect of amine based CO2 capture may be counteracted by the formation of N2O as a minor product in the photo-oxidation of methylamine. Calculations in this work unambiguously show that N2O is not a product in the photo-oxidation of methylamine. The reaction rate coefficients for the OH radical reactions of N-methylformamide and N,N-dimethylformamide have been measured as a function of temperature and pressure by using the flash photolysis laser-induced fluorescence technique. The reactions are significantly slower than the corresponding amine reactions and show a negative temperature dependence. The study further reveals that the amides have a higher potential for nitramine and nitrosamine formation and that they may therefore constitute a previously undisclosed health risk. Kinetic isotope effects for the OH radical reaction of HCN have been measured in a smog chamber through the use of FTIR spectroscopy. The measured values and calculated results confirm that the reaction, unlike the other reactions in this work, mainly occur through an addition channel. The present work has contributed significantly to our understanding of the atmospheric reactions of the intermediates in the atmospheric degradation of methyl amines.

• Rybkin, Vladimir; Helgaker, Trygve & Uggerud, Einar (2014). Development of Direct Born–Oppenheimer Molecular Dynamics with Applications to Water Clusters and Mechanochemistry. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  New methods for Born-Oppenheimer molecular dynamics simulations have been developed and used to study protonated water clusters and mechanochemistry of alkanes. The novel algorithms are an efficient coordinate transformation and sampling microcanonical ensembles of trajectories used for generating starting conditions for simulations. In combination with existing techniques as well as with electronic structure methods within DALTON program, they make it a powerful tool to study reaction dynamics, free of charge. This has been demonstrated by investigation of protonated water clusters relevant for water nucleation in atmospheric chemistry. The structure of the proton salvation shell and evaporation kinetics have been revealed. Another application is the dynamics of alkanes under mechanical stress. Short-chain alkanes – butane and octane – are model compounds for polymers. Their dynamical behavior was simulated and analyzed under two scenarios mimicking the modes ofmechanochemical activation: slow stretching in the atomic-force microscope and violent action of ultrasound.

• Zatula, Alexey; Uggerud, Einar; Helgaker, Trygve & Samdal, Svein (2012). Experimental and computational studies of dynamic processes in ionic water clusters. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Clusters of water molecules mimic the transition from gas phase to bulk water. Cluster species of the desired sizes can be selected using mass spectrometric techniques and their size-dependent properties can thereby be measured. The properties of small ionic clusters are of particular relevance to atmospheric science, providing insights into nucleation phenomena. This work is dedicated to the investigation of properties of selected ionic molecular clusters and their gas phase reactions with heavy water or ammonia, with a strong emphasis on proton transfer phenomena. This has been achieved both experimentally in cluster beam experiments and by quantum chemical calculations. Both in the abundance spectra and the evaporation patterns of the investigated aqueous clusters “magic numbers” discontinuities in otherwise smoothly varying distributions were observed, and are discussed. To further examine a marked difference in the observed “magic-number” behaviour of H+(pyridine)1(H2O)n and H+(NH3)1(pyridine)1(H2O)n clusters, quantum chemical calculations have been employed. Next, relative reaction cross sections were measured for cluster ions reacting with D2O and with NH3 in the collision cell. Analysis of the results for the reaction H+(pyridine)1(H2O)n + NH3 allowed us to improve a kinetic model of the atmospheric positive ion composition. Upon reaction of a cluster with D2O a short-lived reaction intermediate is formed, which is followed by subsequent loss of D2O, HDO or H2O. The reaction channel leading to the loss of HDO requires proton mobility within the cluster, involving O–H-bond activation. The loss of HDO was not observed for protonated water clusters containing one pyridine molecule, a consequence of the immobilizing effect on the extra proton by the nitrogen base site. Similarly, the rates of protium/deuterium exchange for water clusters containing alkali metal ions are consistently extremely low. However, the experiments show enhanced proton mobility in water clusters containing two or three pyridine molecules (H+(pyridine)2–3(H2O)n), in 2,2'-bipyridine and 2,2'-ethylenebipyridine containing water clusters as well as in bisulfate water clusters (HSO4?(H2O)n). On the basis of systematic quantum chemical calculations we present consistent mechanisms for low energy water rearrangement and proton transfer along preformed "wires" of hydrogen bonds between the two distinct sites provided by these core ions in complete support of the experimental findings.

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