TY - JOUR
T1 - Automatic Selection of an Active Space for Calculating Electronic Excitation Spectra by MS-CASPT2 or MC-PDFT
AU - Bao, Jie J.
AU - Dong, Sijia
AU - Gagliardi, Laura
AU - Truhlar, Donald G.
N1 - Funding Information:
This work was supported in part by the Air Force Office of Scientific Research by grant no. FA9550-16-1-0134.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/4/10
Y1 - 2018/4/10
N2 - Multireference methods such as multistate complete active space second-order perturbation theory (MS-CASPT2) and multiconfiguration pair-density functional theory (MC-PDFT) can be very accurate, but they have the disadvantage that they are not black-box methods, and finding a good active space for the reference wave function often requires nonsystematic procedures based on intimate knowledge of the system under study. In this paper, we propose a scheme called the ABC scheme, which is a three-step calculation using three parameters, for automatic selection (without looking at the orbitals and without using any knowledge of the specific system at hand) of the active space (including both the size of the active space and the orbitals in the active space) for MS-CASPT2 or MC-PDFT calculations, and we report tests of the scheme on the first five excitation energies for a set of ten doublet radicals. The results show that the ABC scheme is very successful for both MS-CASPT2 and MC-PDFT for all ten systems considered here.
AB - Multireference methods such as multistate complete active space second-order perturbation theory (MS-CASPT2) and multiconfiguration pair-density functional theory (MC-PDFT) can be very accurate, but they have the disadvantage that they are not black-box methods, and finding a good active space for the reference wave function often requires nonsystematic procedures based on intimate knowledge of the system under study. In this paper, we propose a scheme called the ABC scheme, which is a three-step calculation using three parameters, for automatic selection (without looking at the orbitals and without using any knowledge of the specific system at hand) of the active space (including both the size of the active space and the orbitals in the active space) for MS-CASPT2 or MC-PDFT calculations, and we report tests of the scheme on the first five excitation energies for a set of ten doublet radicals. The results show that the ABC scheme is very successful for both MS-CASPT2 and MC-PDFT for all ten systems considered here.
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U2 - 10.1021/acs.jctc.8b00032
DO - 10.1021/acs.jctc.8b00032
M3 - Article
C2 - 29486125
AN - SCOPUS:85045183248
SN - 1549-9618
VL - 14
SP - 2017
EP - 2025
JO - Journal of Chemical Theory and Computation
JF - Journal of Chemical Theory and Computation
IS - 4
ER -