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Solvatochromic shift of the π → π* transition in all‐trans, cis‐13, cis‐11, cis‐9, and cis‐7 retinal isomers induced by water and methanol
Author(s) -
LópezCastillo Alejandro,
Borin Antonio Carlos
Publication year - 2010
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.22622
Subject(s) - solvatochromism , chemistry , methanol , benzene , time dependent density functional theory , molecule , solvent , retinal , solvent effects , computational chemistry , photochemistry , organic chemistry , biochemistry
Abstract The solvatochromic shift of the lowest singlet π → π* electronic transition in the all‐trans, cis‐13, cis‐11, cis‐9, and cis‐7 retinal isomers were computed under the influence of water, methanol, and benzene solvents. Excitation energies were calculated in gas phase and in solution. The calculations in solution were performed considering the sequential Monte Carlo (MC) /Quantum Mechanical approach. The MC simulations were performed considering the full retinal isomer molecules and 900 water molecules, 900 methanol, or 400 benzene ones. The OPLS/AA parametrization was chosen for retinal, methanol, and benzene molecules and the SPC model was used for water one. From the MC calculations 100 independent configurations were selected, with 100 solvent molecules in thermodynamical equilibrium at T = 298.15 K. Average point‐charges were obtained from those independent configurations for water, methanol, and benzene solvent. TDDFT and CASSCF//CASPT2 methodologies were used to compute the vertical excitation energy of the retinal isomers in different environment. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010