Semi-quantitative description of C hybridization via s- and p-partial density of states probing: An electron spectroscopy study

The paper is a contribution to the characterization of bonding in carbon fi lms. C is unique in establishing different kinds of C-C bonds that are desc ribed in terms of variously hybridized s and p electron states of its VB (V alence Bond). On this basis, the idea is put forward that the s-p hybridiza tion of C in different environments is best characterized if the s- and p-p artial density of states (DOS) are independently mapped. This is made possi ble by sampling the occupied DOS via probes that are selective with respect to the angular momentum symmetry of electron states, such as X-ray excited VB emission (s-selective) and C KVV (K Valence Valence) Auger emission (p; selective). The VB electronic structure appears to be well-characterized in this way. Systems made of purely sp(2) or purely sp(3)-hybridized carbons are unambiguously singled out while for systems where the two hybridization s coexist, the ability to reveal changes in the relative amount of sp(2) an d sp(3) hybridized carbons is demonstrated. (C) 2000 Elsevier Science B.V. ALL rights reserved.