Predissociation of Bi2 A(0u+), v'=21-39

Area of Science:

• Molecular Spectroscopy
• Chemical Physics
• Quantum Mechanics

Background:

• The Bismuth dimer (Bi2) molecule's A(0u+) state is crucial for understanding molecular dissociation dynamics.
• Predissociation, the process where a molecule transitions from a bound state to a dissociative state, influences molecular lifetimes.

Purpose of the Study:

• To measure collisionless lifetimes of Bi2 A(0u+) states for vibrational levels v'=20-39 and rotational levels J'<=105.
• To investigate the influence of predissociation on these molecular lifetimes.
• To characterize the rates of predissociation as a function of vibrational and rotational quantum numbers.

Main Methods:

• Utilized pulsed laser-induced fluorescence techniques to probe Bi2 molecules.
• Employed traditional lifetime measurements to determine decay rates.
• Applied synthetic spectrum fits to laser excitation spectra to resolve dense spectral features.

Main Results:

• Measured collisionless lifetimes for Bi2 A(0u+) states across a range of vibrational and rotational levels.
• Observed rapid predissociation rates, varying from 1.53x10^2 s^-1 (v'=21) to 1.5x10^5 s^-1 (v'=39).
• Found that a single repulsive potential could not fully explain the observed vibrational dependence of predissociation rates.

Conclusions:

• The predissociation process in the Bi2 A-state is significant and varies with vibrational and rotational states.
• The complexity of the Bi2(A-->X) spectrum necessitates advanced spectroscopic methods for accurate rate determination.
• Further theoretical investigations are required to model the observed predissociation dynamics accurately.