[OPTICAL REVIEW Vol. 6, No. 3 (1999) 237-241]

Theoretical Study on the Second Hyperpolarizabilities for Small Radical Systems*

Satoru YAMADA, Masayoshi NAKANO, Masamichi NISHINO and Kizashi YAMAGUCHI

Department of Chemistry, Graduate School of Science, Osaka University, Osaka, 560-0043 Japan

(Received December 7, 1998; Accepted December 28, 1998)

We study the second hyperpolarizabilities (γ) for anion, neutral and cation radicals and find that magnitudes of γ (|γ|) of the radicals are sensitively influenced by features of each charged state. It is also found that electron-correlation dependence of γ could be related to the resonance structure contributing to the ground state of the molecules.

Key words : third-order nonlinear optical response, second hyperpolarizability, open-shell systems, iso-electronic systems, charged radical