Solvent electronic polarization effect on the electronic transitions in solution: Charge polarizable reference interaction site model self-consistent field approach

Abstract

Effect of the electronic polarization in solvent on the solvatochromic shift for the excitation energy of solute molecule is studied by the reference interaction site model self-consistent field (RISM-SCF) method. The electronic polarization in solvent molecule is represented by the charge response kernel (CRK) obtained by ab initio calculations. Employing the CRK, a charge polarizable RISM-SCF method is proposed for describing the electronic structure of solute molecules in solution and estimating the excitation energies. The excitation energy for nπ* transition of acetone is calculated in CH3CN, CHCl3, CCl4, and CS2 solvents and the solvent electronic polarization effect on the solvation shift is examined. As a result, a blue shifts of 1225, 675, 166, and 92 cm−1 is obtained in those solvents. Furthermore, the solvation shifts in the transitions to the 11B1, 11B2, and 21A1 states of pyridine are evaluated in the same solvents. A blue shift is observed for the 11B1 ← 11A1 transition in all the solvent, while the 21A1 ← 11A1 one shows a red shift.