Photoemission from valence bands of transition metal-phthalocyanines

Angular dependencies of ultraviolet photoelectron spectrum of transition metal-phthalocyanines (TM-Pcs), NiPc and CoPc, have been studied by using multiple-scattering theory to explore the electronic structure of the organometallic complexes influenced by central metal atom. The calculated angular distributions of photoelectrons for the highest occupied molecular orbital (HOMO: a(1u)) from the two single systems are nearly the same and represent well the experimental results obtained for the well-ordered monolayer on the highly oriented pyrolytic graphite substrate. The central metal atoms almost have no contribution on the HOMO distribution, which mainly comes from the carbon atoms of Pc ring. Moreover, the modification of the distribution for pi orbital upon adsorption as well as the scattering effects of the central metal on the photoemission intensities are negligible for the major. (C) 2010 Elsevier B.V. All rights reserved.