posted on 2022-01-11, 18:36authored byKe Wang, Zhaoxuan Xie, Zhen Luo, Haibo Ma
We
develop an automatic and efficient scheme for the accurate construction
of the bases for excitonic models, which can enable “black-box”
excited state structure calculations for large molecular systems.
These new and optimized bases, which are named the block interaction
product state (BIPS), can be expressed as the direct products of the
local states for each chromophore. Each chromophore’s local
states are selected by diagonalization of its reduced density matrix,
which is obtained by quantum chemical calculation of the small subsystem
composed of the chromophore and its nearest neighbors. We implemented
the BIPS framework with fragment-based calculations considering two-
and three-body interactions. Test calculations for eight different
molecular aggregates demonstrate that this framework provides an accurate
description of not only the excitation energies but also the first-order
wave function properties (dipole moment and transition dipole moment)
of the low-lying excited states at a low-scaling computational cost.