Abstract
A series of carbon nitride structures have been generated, by using a classical potential in a Metropolis Monte Carlo liquid quench procedure. The resulting structures are relaxed further using the density functional theory approach. Structures are generated for various mass densities and varying N/C ratio so that all possible CโN bonding configurations are produced. Structural analysis of the equilibrated structures are performed and the effect of nitrogen inclusion on the formation of curved carbon systems is evidenced. Density of states and energyโloss nearโedge structure calculations show that nitrogen incorporation modifies the valence and conduction bands of amorphous carbon (aโC). Xโray photoelectron spectroscopy (XPS) calculations within the firstโprinciples methodology are also performed on the generated aโC nitride systems. Depending on the carbon bonding configuration, the carbon 1s energies are found to vary from 283 eV to 288 eV while those of nitrogen are found to range from 397 eV to 402 eV. The experimentally observed N 1s XPS features of aโC nitride systems are correlated with the nitrogen bonding state with carbon, the degree of delocalization of the nitrogen lone pair and the CโN bond length. In particular, our calculations support the interpretation of the N 1s feature at an energy of about 398.4 eV to twoโcoordinated N atoms whose immediate neighbors enhance a delocalization of the N lone pair of electrons. (ยฉ 2006 WILEYโVCH Verlag GmbH & Co. KGaA, Weinheim)