Characterization of a shallow-bound 0g+ valence state of I2 using emission from the D 0u+(3P2) and F′ 0u+(1D2) ion-pair states populated by amplified spontaneous emission

Abstract

A range of vibrational levels of the D 0_u⁺(³P₂) and F′ 0_u⁺(¹D₂) ion-pair states of I₂ is shown to be easily generated by amplified spontaneous emission (ASE) from their more accessible partners, E 0_g⁺(³P₂) and f′ 0_g⁺(¹D₂), in sufficient concentration for dispersed fluorescence studies of the D 0_u⁺(³P₂) → 0_g⁺(bb) and F′ 0_u⁺(¹D₂) → 0_g⁺(bb) transitions to be carried out. T₀ (J = 49) of this shallow-bound 0_g⁺(bb) valence state is unambiguously determined and an improved R_e value of 3.952 ± 0.005 Å is obtained from optimizing the fit of the intensities of the vibrational progressions in the 0_g⁺(bb) state, and T_e is found to be 27311.3 ± 2 cm⁻¹, leading to D_e = 442.0 ± 2 cm⁻¹.