Conical intersections of free energy surfaces in solution: Effect of electron correlation on a protonated Schiff base in methanol solution

Journal Article · Sat Aug 14 00:00:00 EDT 2010 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3472033· OSTI ID:21559896

Mori, Toshifumi; Nakano, Katsuhiro; Kato, Shigeki ^[1]

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1. Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)

The minimum energy conical intersection (MECI) optimization method with taking account of the dynamic electron correlation effect [T. Mori and S. Kato, Chem. Phys. Lett. 476, 97 (2009)] is extended to locate the MECI of nonequilibrium free energy surfaces in solution. A multistate electronic perturbation theory is introduced into the nonequilibrium free energy formula, which is defined as a function of solute and solvation coordinates. The analytical free energy gradient and interstate coupling vectors are derived, and are applied to locate MECIs in solution. The present method is applied to study the cis-trans photoisomerization reaction of a protonated Schiff base molecule (PSB3) in methanol (MeOH) solution. It is found that the effect of dynamic electron correlation largely lowers the energy of S{sub 1} state. We also show that the solvation effect strongly stabilizes the MECI obtained by twisting the terminal C=N bond to become accessible in MeOH solution, whereas the conical intersection is found to be unstable in gas phase. The present study indicates that both electron correlation and solvation effects are important in the photoisomerization reaction of PSB3. The effect of counterion is also examined, and seems to be rather small in solution. The structures of free energy surfaces around MECIs are also discussed.

• OSTI ID: 21559896
• Journal Information: Journal of Chemical Physics, Vol. 133, Issue 6; Other Information: DOI: 10.1063/1.3472033; (c) 2010 American Institute of Physics; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CHEMICAL BONDS
ELECTRON CORRELATION
FREE ENERGY
ISOMERIZATION
METHANOL
MOLECULES
OPTIMIZATION
PERTURBATION THEORY
PHOTOCHEMISTRY
REACTION KINETICS
SCHIFF BASES
SOLUTES
SOLUTIONS
SOLVATION
SURFACES
THERMODYNAMICS
ALCOHOLS
CHEMICAL REACTIONS
CHEMISTRY
CORRELATIONS
DISPERSIONS
ENERGY
HOMOGENEOUS MIXTURES
HYDROXY COMPOUNDS
IMINES
KINETICS
MIXTURES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES