Theoretical study of a new molecular ion species BeN+: molecular states and cross sections for electronic excitation and dissociation

Abstract

We present here a theoretical study of a new molecular ion species BeN⁺, which has not been reported before. Using a good quality configuration interaction model, we first undertake a configuration interaction calculation of the molecular states to obtain the potential energy curves of several low lying states of BeN⁺ and the dipole and transition dipole moments of some of its states as a function of the internuclear distance. We find the ground state to be bound and of X ³Σ⁻ character having a shallow minimum at R_e = 2.9031a₀ and several other closely spaced excited states some of which are repulsive. We have determined the spectroscopic parameters for some of these states by fitting the raw potential energy data to a 6-parameter analytical potential energy function. Subsequently, the R-matrix method is used to obtain electron collision cross sections for electronic excitation from the ground X ³Σ⁻ state to several of its excited states at the equilibrium R_e = 2.9031a₀ and cross sections for electron impact dissociation. We have also reported many Feshbach resonances and their widths at the equilibrium R_e = 2.9031a₀, which may, in future studies, be extended to potential energy curves for neutral dissociative states. The states and cross sections obtained are of considerable significance for edge plasma chemistry in fusion devices operating with beryllium walls.