Femtosecond optical Kerr study of heavy-atom effects on the third-order optical non-linearity of thiophene homologues: electronic hyperpolarizability of tellurophene

Second hyperpolarizability gamma of tellurophene (C4H4Te), a tellurium-containing homologue of thiophene, was measured by optically heterodyne-detected optical Kerr effect (OHD-OKE) experiments. We found that the gamma of tellurophene was + 6.3 x 10(-36) esu and was larger than twice of that for selenophene and almost three times that for thiophene. The large gamma for tellurophene as the homologue was discussed in terms of the symmetry species of the two lowest excited states and their transition energies from the ground state under the 3-state approximation. Low-lying excited A(1) state is presented as the plausible cause of the large gamma. (C) 1999 Elsevier Science B.V. All rights reserved.