Experimental and theoretical studies on the excited state polarizabilities of benzene, naphthalene, and anthracene

Through electric field perturbation techniques, the change in the trace of the polarizability tensor upon electronic excitation, as well as one component of that tensor, have been determined for the 1La and 1Lb transitions in naphthalene and for the 1La transition in anthracene. Also, a revised estimate of the change in the in-plane polarizability for the 1A1g→1B2u (1Lb) transition in benzene is given. These experiments have been carried out on the 0–0 band for the 1La transitions and on the first vibronically allowed band for the 1Lb transitions. In all cases, these experiments were performed with the aromatic hydrocarbon dissolved in a rigid amorphous solution of 3-methylpentane (3-MP) at 77°K. These results are compared with values derived from π-electron (PPP-SCF) and all valence electron (CNDO/S) calculations. Finally, computed ground state polarizabilities are compared with existing experimental results, and calculations of electric field induced oscillator strengths for the 1La and 1Lb transitions in benzene are reported.