Computational studies of interstellar silicon-nitrogen molecular species

Ab initio and hybrid density functional theory (DFT) studies were performed in order to determine the stability of small silicon-nitrogen compounds. R esults obtained with the highest level of ab initio studies currently avail able (the quadratic complete basis set, CBSQ) were used as a reference to c ompare results generated with other ab initio and DFT computational studies . The isomerization barriers, ionization potentials, electron affinities, a nd proton affinities for some of these molecular systems were computed. The values computed with CBSQ and hybrid DFT methods were in good agreement wi th each other. This suggests that these molecular species are more stable w hen hydrogen is attached to nitrogen which is contrary to carbon analogs wh ich prefer hydrogen bound to the carbon atom. A comparison between DFT and high level ab initio values was used to determine the accuracy of DFT metho ds to evaluate silicon-nitrogen compounds. (C) 1998 Elsevier Science B.V. A ll rights reserved.