ct9b01162_si_001.pdf (2.34 MB)
Avoiding Electron Spill-Out in QM/MM Calculations on Excited States with Simple Pseudopotentials
journal contribution
posted on 2020-02-25, 19:36 authored by Alireza Marefat
Khah, Peter Reinholdt, Jógvan Magnus
Haugaard Olsen, Jacob Kongsted, Christof HättigQM/MM calculations of electronic
excitations with diffuse basis
sets often have large errors due to spill-out of electrons from the
quantum subsystem. The Pauli repulsion of the electrons by the environment
has to be included to avoid this. We propose transferable atomic all-electron
pseudopotentials that can readily be combined with most MM force fields
to avoid electron spill-out. QM/MM excitation energies computed with
time-dependent Hartree–Fock and the algebraic diagrammatic
construction through second-order are benchmarked against supermolecular
calculations to validate these new pseudopotentials. The QM/MM calculations
with pseudopotentials give accurate results that are stable with augmentation
of the basis set with diffuse functions. We show that the largest
contribution to residual deviations from full QM calculations is caused
by the missing London dispersion interaction.