Speaker
Description
Calculation of binding energies of molecular crystals with accurate methods based on quantum mechanics is difficult. The main reason is the need to describe correlations in, in principle, infinite systems, but the calculations tend to be non-trivial to set-up and analyze. The first problem can be ameliorated by using so called many-body expansion (MBE). In this approach the binding energy is calculated from a very large number of calculations, each of which involves only up to few molecules of the crystal. Importantly, the MBE scheme gives us also a way to assess the accuracy of more approximate theoretical approaches. We will show some of our results aimed at understanding such methods, especially those that are widely used to study molecular solids [1,2]. Furthermore, we will show how accurate binding energies can be obtained from a combination of results obtained within periodic boundary conditions and MBE values.
[1] Pham, Modrzejewski, Klimes, J. Chem. Phys. 158, 144119 (2023)
[2] Pham, Modrzejewski, Klimes, J. Chem. Phys. 160, 224101 (2024)
