TY - JOUR
T1 - Unveiling Controlling Factors of the S0/S1 Minimum Energy Conical Intersection
T2 - A Theoretical Study
AU - Nakai, Hiromi
AU - Inamori, Mayu
AU - Ikabata, Yasuhiro
AU - Wang, Qi
N1 - Funding Information:
Some of the present calculations were performed at the Research Center for Computational Science (RCCS), Okazaki Research Facilities, Institutes of Natural Sciences (NINS). This study was supported in part by a Grant-in-Aid for Scientific Research “KAKENHI 18K14184” from the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
Publisher Copyright:
© Copyright 2018 American Chemical Society.
PY - 2018/11/15
Y1 - 2018/11/15
N2 - The minimum energy conical intersection (MECI) geometries play an important role in photophysics and photochemistry. Although a number of MECI geometries can be identified using quantum chemical methods, their chemical interpretation remains unclear. In this study, a systematic analysis was performed on the MECIs between the singlet (S0) and lowest singlet excited (S1) states of organic molecules. The frozen orbital analysis (FZOA), which approximates the excited states with minimal main configurations, was adopted to analyze the excitation energy components at the S0/S1 MECI geometries as well as the S0 and S1 equilibrium geometries. At the S0/S1 MECI geometries, the HOMO-LUMO gaps decreased as expected but did not disappear. The remaining gaps were balanced with the HOMO-LUMO Coulomb integrals. Furthermore, we discovered that the HOMO-LUMO exchange integrals became approximately zero. On the basis of this fact, a systematic interpretation of the S0/S1 MECI geometries has been described.
AB - The minimum energy conical intersection (MECI) geometries play an important role in photophysics and photochemistry. Although a number of MECI geometries can be identified using quantum chemical methods, their chemical interpretation remains unclear. In this study, a systematic analysis was performed on the MECIs between the singlet (S0) and lowest singlet excited (S1) states of organic molecules. The frozen orbital analysis (FZOA), which approximates the excited states with minimal main configurations, was adopted to analyze the excitation energy components at the S0/S1 MECI geometries as well as the S0 and S1 equilibrium geometries. At the S0/S1 MECI geometries, the HOMO-LUMO gaps decreased as expected but did not disappear. The remaining gaps were balanced with the HOMO-LUMO Coulomb integrals. Furthermore, we discovered that the HOMO-LUMO exchange integrals became approximately zero. On the basis of this fact, a systematic interpretation of the S0/S1 MECI geometries has been described.
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U2 - 10.1021/acs.jpca.8b07864
DO - 10.1021/acs.jpca.8b07864
M3 - Article
C2 - 30252469
AN - SCOPUS:85054813706
SN - 1089-5639
VL - 122
SP - 8905
EP - 8910
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 45
ER -