Intermolecular Relaxation Energies in Anthracene

Abstract

A type of angle-dependent uv photoemission measurement has been used to study variations in the intermolecular polarization effect at the surface of thin condensed anthracene films. The top molecular layer exhibits a 1.2-eV relaxation energy in response to the polarization of the hole state created in photoemission event. The second and subsequent layers exhibit a different value of about 1.5 eV. This result corresponds to the observation of a surface electronic molecular-ion state on a molecular solid.