Spectroscopic Constants, Lifetimes and Predissociation Rates for Bi2A(0+u)

Michael W. Dolezal

Plain-text title: Spectroscopic Constants, Lifetimes and Predissociation Rates for Bi2A(0u+)


This research determined spectroscopic constants, lifetimes and predissociation rates for the A-state of Bi2. More than 100,000 spectral features from a Bi2 X to A absorption spectrum, encompassing 0 < v' < 92, 0 < v" < 7, and J < 204, have been assigned. Vibrational and rotational spectroscopic constants for Bi2(A) were improved. These constants redefine the A-state potential using RKR methods and set the A-state dissociation energy at 29913 1/cm correlating A-state dissociation products to quartet S + doublet D atoms. A pulsed dye laser apparatus was used to obtain lifetime data for Bi2 A to X transitions. The collision-free lifetimes for v' = 20 to v' = 39, and J < 105, were investigated for effects of heterogeneous predissociation. observed predissociation rates, kpd J(J+1), establish the range kpd = 153 to 1.5 E+05 1/sec for v' = 21 to v' = 39. Rapid predissociation and the dense Bi2 (A-X) spectrum required both traditional lifetime measurements and synthetic spectrum fits to determine the full range of observed rates. Numerical analysis fails to produce a repulsive potential responsible for predissociation implying that current theoretical knowledge of predissociation is inadequate to describe the results of this study.