Ground X 2Σ+ state potential well, and excited state dynamics of diatomic XeF in solid Ne and Ar

Abstract

The ’’shape’’ of the ground state potential well of XeF in solid Ne has been obtained from an analysis of D (1/2) →X ²Σ⁺ resonance fluorescence. The constants ω_e^″=247 cm⁻¹ and ω_ex_e^″=10.2 cm⁻¹ give an extrapolated Morse oscillator D_e?1500 cm⁻¹. The ground state well is only slightly deeper in the solid than in the gas phase (D_e?1160 cm⁻¹). In solid Ar, the T_e values for the excited D (1/2) and B (1/2) states undergo unprecedented red shifts of ?8% and ?13% respectively, apparently reflecting the charge transfer nature of these excited states. The extrapolated gas phase radiative lifetimes are τ_r=13±1 nsec for D (1/2), and τ_r=8±2 nsec for B (1/2). Polarized fluorescence studies prove that the gas phase 3500 Å lasing transition is B (1/2) →X ²Σ⁺. The influence of the T_e red shift upon the excited state dynamics, and upon the X ²Σ⁺ well depth in the solid, is discussed. Unassigned emission spectra are also observed from other van der Waals complexes among Xe and F atoms.