Electronic Structure of Vanadyl Phthalocyanine. Investigations of Thin Film Samples by Electron Energy‐Loss Spectroscopy

The energy‐loss function Im (−ε −1 ) of a thin polycrystalline vanadyl phthalocyanine film is determined in the range from 1 to 37 eV from energy‐loss experiments with 50 keV electrons. The electronic structure of the film investigated is analyzed by computing the complex dielectric function ε( E ), optical constants ( n(E) + ik(E) , R(E) , α( E )), and n eff ( E ) using the Kramers‐Kronig analysis of the energy‐loss function. The spectrum of valence electron excitations is primarily interpreted in terms of π−π* and σ−σ* transitions of individual molecules and in terms of the collective excitation of the valence electron ensembles (σ + π plasmon).