Electronic States and Excitations in Polymers

Abstract

The most common probe of the electronic structure of matter is light. However, for many polymeric materials the fundamental electronic excitation spectrum is beyond the range of common optical spectrometers. For these materials electron energy loss spectroscopy is a particularly attractive technique for measuring the spectrum of electronic excitations, thus providing key information for the basic understanding of the nature of the electronic states. The experiments reported here measured energy loss spectra of an 80 keV electron beam transmitted through thin samples (~100 nm thick) which were prepared by standard solvent casting techniques or polymerized in thin film form. The special purpose high resolution energy loss spectrometer used in these studies was operated with a resolution of 0.1 eV. Spectra were recorded as a function of scattering angle (or momentum transfer) over the energy range 0.2 to 400 eV, thus encompassing both valence and core electronic excitations. Radiation induced changes