Abstract
This manuscript introduces a methodology (within the Born-Oppenheimer picture) to compute electronic ground-state properties of molecules and solids/surfaces with fractionally occupied components. Given a user-defined division of the molecule into subsystems, our theory uses an auxiliary global Hamiltonian that is defined as the sum of subsystem Hamiltonians, plus the spatial integral of a second-quantized local operator that allows the electrons to be transferred between subsystems. This electron transfer operator depends on a local potential that can be determined using density functional approximations and/or other techniques such as machine learning. The present framework employs superpositions of tensor-product wave functions, which can satisfy size consistency and avoid spurious fractional charges at large bond distances. The electronic population of each subsystem is in general a positive real number and is obtained from wave-function amplitudes, which are calculated by means of ground-state matrix diagonalization (or matrix propagation in the time-dependent case). Our method can provide pathways to explore charge-transfer effects in environments where dividing the molecule into subsystems is convenient and to develop computationally affordable electronic structure algorithms.
Original language | English (US) |
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Article number | 034105 |
Journal | Journal of Chemical Physics |
Volume | 149 |
Issue number | 3 |
DOIs | |
State | Published - Jul 21 2018 |
Funding
This work was supported by the Air Force Office of Scientific Research MURI (Grant No. FA9550-14-1-0003) for applications and by the Department of Energy Grant No. DE-SC0004752 for theory. M.A.M. thanks Dr. Carlos Borca (Georgia Tech) and Dr. Bo Fu (Northwestern University) for helpful discussion.
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry