A reduction of the high symmetry of C60 in a PMMA polymer film as revealed by electroabsorption spectra

Abstract

The absorption band of C60 and C70 located at 331 nm and 380 nm, respectively, in a PMMA polymer film shows a strong electric field effect, and the observed electroabsorption spectra are simulated by a superposition of the absorption spectrum, its first and the second derivative spectra, suggesting that electric dipole moment and molecular polarizability change following excitation into these bands. The presence of the electric dipole moment implies that inversion center does not exist in a polymer film not only on C70 but also on C60 in the ground state or/and the excited state.