Quantum chemistry is traditionally taught at later stages of an undergraduate chemistry programme, since it requires prior knowledge of calculus, linear algebra, programming and quantum mechanics. Even when equipped with this understanding, the challenges posed by deeply rooted programming languages like Fortran, highly intricate approximative techniques, and the sheer complexity of the many-body quantum problem can be off-putting for students.
Yet at its core, the problem is rather straightforward. As Richard Feynman once laid it out, atoms “move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into noe another. “ Without this behaviour, nature would have little structure for us to observe, and not much would change over time. So how do we predict this behaviour?
Seeing structure in something like a snow crystal is one thing, but understanding it on the microscopic level requires more than a microscope: it demands theory and simulation.
At Hylleraas, we wanted to provide the many high-schoolers visiting us for UNGFORSK this september with an opportunity to actually do some theoretical chemistry themselves. For this, we invited them on an imaginary journey, where they were gradually shrunk to smaller scales, ultimately reaching the level of the electrons.
At each scale, they were given problems to conquer and observations to make sense out of, aided by interactive simulations and visualization tools. At the size of molecules, in a gas at low temperature, they were tasked with figuring out why their world just turned dark and lonely. Evidently, inhabiting and ideal gas is not that much interesting.
A sudden pressure wave changed it all, however, and they furthermore explored wave-behavior and the transition into liquids as the temperature decreased. At some point, it all turned solid, which finally allowed them probe the electron density of a single watermolecule embedded in ice.
Over two eventful days, more than a hundred bright high-schoolers visited the Hylleraas Centre for Quantum Molecular Sciences. Curiosity sparked and mysteries were unraveled. For most of them, this was their first encounter with theoretical chemistry. For some, this may have been the first out of many, in which case we hope to see them return one day.