Electronic Spectroscopy of the AlSb Molecule: A Theoretical Study

Abstract

Relativistic configuration interaction calculations are carried out to study the electronic spectrum of the AlSb molecule. Potential energy curves of 44 electronic states within 6 eV of energy are constructed. Spectroscopic constants (re, ωe, Te, De, μe) of the low-lying Λ-S states are computed. The equilibrium bond length and vibrational frequency of the ground state (X3Σ-) of AlSb are estimated to be 2.79 Å and 249 cm-1, respectively. Effects of the spin−orbit coupling on the spectroscopic properties and potential energy curves of states that correlate with the lowest two dissociation limits are investigated. The computed dissociation energy of the ground-state spin component (X3 ) is 1.44 eV. Transition moments of several electric dipole-allowed and spin-forbidden transitions are computed from CI wave functions. Radiative lifetimes of the low-lying excited states of AlSb at the lowest three vibrational levels (v‘ = 0, 1, 2) are estimated. Transitions from the 33Π0+ component to all lower states with ΔΩ = 0, ±1 are predicted. At v‘ = 0, the 33Π0+ component has a lifetime of about 1.26 μs. The electronic states of AlSb are also compared with those of isovalent AlP, GaAs, GaSb, and InSb molecules.