Knowledge Bank

The absorption spectra of benzene and naphthalene, in an electric field, have been measured in frozen solution of 3-methylpentane at $77\circ K$ . By varying the angle between the electric field and the light ‘s polarization vector, two molecular parameters can be determined. These are the trace of the change in the polarizability tensor upon electronic excitation, and another function of the components of this tensor. When the ground state polarizability tensor is known, the excited state polarizability can be determined from this data. The ground and excited state polarizability tensors have been calculated in the PPP-SCF and CNDO/S approximations. These theoretical results will be compared with the experimental values for the linear polyacenes from benzene to tetracene. We wish to thank the National Science Foundation and the Material Science Center of Cornell University for grants in support of this work.