Ab initio structures and stabilities of helide cations: (X = B-Ne, Al-Ar and n = 1-3)

The electronic structure and molecular properties of helides of the form (where , Al-Ar and ) were studied using the CCSD(T) method in conjunction with the series of correlation-consistent basis sets. The highest level of theory employed, the CCSD(T)_-FC/cc-pVQZ model, was used to elucidate trends in bond lengths, dissociation energies and harmonic frequencies. The more highly charged species were found to have shorter bond lengths than the singly charged species. The ground states of the helide cations were often those with longer bond lengths when compared with the excited state ions. Received: 11 May 1998 / Received in final form: 2 September 1998