Vibrational-to-translational energy transfer between the lowest vibrational levels (v′=0–4) of the A(0+u) state of Bi2 has been investigated using spectrally resolved, laser-induced fluorescence techniques. The small vibrational spacing (ω′e≃132 cm−1) leads to highly nonadiabatic conditions, particularly for the Bi2(A)–He collision pair. However, the Δv=−1 transition probabilities for collisions with the rare gases range from 0.75% to 1.75% per collision, considerably lower than would be anticipated from standard vibrational energy transfer theory. Multiquantum (Δv′=±2) transfer rates are low, consistent with the low anharmonicity of the A(0+u) state. The rates for Δv′=±1 transitions scale linearly with vibrational quantum number as expected near the bottom of this nearly harmonic potential.
The Journal of Chemical Physics
Robert E. Franklin, Glen P. Perram; Collisional dynamics of Bi2 A(0+u). I. Quantum-resolved vibrational energy transfer for v′=0–4 . J. Chem. Phys. 1 October 1999; 111 (13): 5757–5763. https://doi.org/10.1063/1.479872