Second hyperpolarizability of phenalenyl radical system involving acetylene pi-conjugated bridge

Ohta S; Nakano M; Kubo T; Kamada K; Ohta K; Kishi R; Nakagawa N; Champagne B; Botek E; Umezaki SY; Takebe A; Takahashi H; Furukawa SI; Morita Y; Nakasuji K; Yamaguchi K

Chemical Physics Letters, Vol.420, No.4-6, 432-437, 2006

DOI10.1016/j.cplett.2006.01.022 Export Citation

Second hyperpolarizability of phenalenyl radical system involving acetylene pi-conjugated bridge

Ohta S, Nakano M, Kubo T, Kamada K, Ohta K, Kishi R, Nakagawa N, Champagne B, Botek E, Umezaki SY, Takebe A, Takahashi H, Furukawa SI, Morita Y, Nakasuji K, Yamaguchi K

The static second hyperpolarizability (gamma) of a singlet diradical system involving phenalenyl radicals linked with acetylene pi-conjugated bridge, BPLE, is investigated as well as reference closed-shell systems, BPRY1 and BPRY2, by the hybrid density functional theory method. The gamma value of BPLE with intermediate diradical character is shown to be about four times as large as that of BPRY1 with similar pi-conjugation length and to be about twice as large as that of BPRY2 with longer pi-conjugation length. This feature is in agreement with our prediction that the molecules with intermediate diradical characters enhance y values compared to the closed-shell molecules. (c) 2006 Elsevier B.V. All rights reserved.