Radiative and nonradiative lifetimes for vibrational levels of the A 1Σ+ state of 7LiH

Abstract

Newly calculated radiative transition probabilities for the A ¹Σ⁺→X ¹Σ⁺ (v′–v^″) emission bands of ⁷LiH (preceding paper) are used to calculate the radiative lifetime of the various vibrational levels (0⩽v′⩽26) of A ¹Σ⁺ LiH. For higher levels an estimate of the bound‐to‐free emission probability is also needed and included. For the highest two levels, A ¹Σ⁺→B ¹Π emission is possible and has been included, but makes a negligible contribution to the radiative lifetime. The calculated radiative lifetimes increase with v′ from 28.9 nsec at v′=0 to 36.1 nsec at v′=16 and then decrease to 27.1 nsec at v′=26. They are found to be in good agreement with measured total lifetimes, implying the nonradiative (predissociative) lifetime for the measured levels is ≳10⁻⁷ sec, in accord with simple theoretical expectations.