The linear optical polarizability spectra of five C-78 isomers

Effects of anisotropy, symmetry, atom arrangement and Coulomb interaction o n the linear optical polarizability spectra of five C-78 isomers are theore tically studied by using the extended Su-Schrieffer-Heeger model with and w ithout Coulomb interaction. The main results are as follows. 1) The spectra become anisotropic with respect to the direction of the electric field of light. The property is common in the model with and without Coulomb interac tion. 2) The symmetry and atom arrangement have great effects on the peak p ositions, strengths, and number. 3) The Coulomb interaction tends to shift peaks to higher energies and enhances the oscillator strengths at higher en ergies.