Change of C–C Bond Length in Layers of Graphite Upon Charge Transfer

ABSTRACTTight binding crystal orbital calculations on infinite layers of graphite have been performed for charge transfer (q) values ranging from −0.15 to +0.15 e/carbon atom. The rC-C carbon-carbon bond lengths have been optimized at several q values. The change of the calculated rC-C values as a function of q fits very well with the experimentally observed variations of the C-C bond lengths of both acceptor and donor compounds of intercalated graphite. The asymmetry of the variation of rC-c with respect to the sign of the charge transfer is related to the slightly antibonding nature (at the level of second neighbor interactions) of the π-electrons around the Fermi level of pristine graphite, similar to those in polyacetylene.