On the stability of the autodissociative ground electronic state of BeH²⁺

Abstract

A B S T R A C T -It is shown that the mechanism of spontaneous infrared emission enhances substantially the stability of the long-lived ground electronic state of the exotic BeH2+, whose autodissociation becomes possible only via tunneling. The system, initially situated in any vibrational level (except the high-lying ones for which dissociation is predominate) and statistically distributed over all rotational states, reaches stability through a cascade of dipole emissions toward lower levels. The rapid spatial variation of the dipole moment results in fast radiative processes and might suggest experimental observations easier to perform. The methodology is based on a recently presented analytic discrete variable representation (DVR) potential energy surfaces (PES) of an unusual topology. At small interatomic distances, suchPES display a deep well, which can support a number xtensive theoretical and experimental reof vibrational levels. They are all, however, located far above the dissociation threshold, in the continuum of the fragments. The dissociation of the metastable complex into its singly ionized atomic constituents is obstructed by a high barrier, formed

Theoretical investigation of the low-lying electronic states of the alkaline hydride BeH2+ ion: Potential energy curves, spectroscopic constants, vibrational levels, and transition dipole functions

“…Also Bruna et al [10] have determined the equi librium nuclear distance R min and the frequency of harmonic vibrational ω e for the alkaline hydride BeH 2+ ion in its ground state. Several other theoretical studies [11][12][13][14] have predicted the existence of the Barofsky and Müller [16], using a magnetic sector field ion atom probe to identify ions formed by field evaporation from a beryllium tip exposed to a mixture of H 2 and D 2 . Despite this great interest, a comprehensive theo retical study for the structure and the electronic prop erties of the alkaline hydride BeH 2+ ion is still missing, especially for the higher excited states.…”