Polar solvation dynamics: A combination of the reference interaction-site model and mode-coupling theories

Nishiyama, K.; Yamaguchi, T.; Hirata, Fumio; Okada, T.

doi:10.1351/pac200476010071

Pure Appl. Chem., 2004, Vol. 76, No. 1, pp. 71-77

http://dx.doi.org/10.1351/pac200476010071

Polar solvation dynamics: A combination of the reference interaction-site model and mode-coupling theories

K. Nishiyama, T. Yamaguchi, Fumio Hirata and T. Okada

Venture Business Laboratory, Osaka University, Suita, Osaka 565-0871, Japan; Department of Molecular Design and Engineering,Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, Aichi 464-8603, Japan; Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan; Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan

Abstract: We employ the reference interaction-site model (RISM) theory for solvation dynamics of simple ions in acetonitrile. For the description of time evolution of solvent relaxation, we apply the mode-coupling theory recently developed by Yamaguchi and coworkers [Mol. Phys. 101, 1211 (2003)]. The combination of the RISM/mode-coupling theory is used for the calculation of the dynamic response function, S_S(t), which measures the relaxation of average energy of the solute-solvent system. S_S(t) decays with the Gaussian plus underdamped curves in the time duration of first 1 ps, followed by slow, long-tailed components down to tens of picoseconds. We show that the RISM/mode-coupling framework is applicable rather well for the detailed description of solvation dynamics at the molecular level.