Polarizability of Molecules in Excited Electronic States

Abstract

In an earlier paper we reported the first measurement of the optical anisotropy of a molecule in an excited electronic state by the method of induced birefringence. In the present paper details are presented for the application of this method to the determination of the differences in the components of the polarizability tensors between an excited electronic and ground state. Experimentally we studied naphthalene-d8 in EPA at 77°K from 4200 to 6300 Å. Our measurement of the dispersion of the polarizability near the triplet—triplet absorption provides evidence for the existence of a previously suspected weak triplet state approximately 18 000 cm−1 above the lowest-lying triplet state.