An ab initio study of the interaction of alkali metals with the HCN/HNC system

An investigation into the effect of the introduction of alkali metal (lithium and sodium) atoms and cations on the hydrogen cyanide (HCN)/hydrogen isocyanide (HNC) system is reported. For the neutral species, it is found that the minima located fall into two distinct groups, van der Waals and charge transfer type complexes similar to those species observed in isoelectronic systems such as MC2H2, M = Li, Na. For the cationic species only the van der Weals type complexes were located. The location of the transition states connecting the minima described allowed a comparison to be made between the energy barrier for the free isomerisation reaction HCN --> HNC and that in the presence of the metal atom or cation. These results show that, unlike in the acetylene --> vinylidene system, no catalytic effect is observed. (C) 2000 Elsevier Science B.V. All rights reserved.