Document Type


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Journal/Book/Conference Title

The Journal of Chemical Physics





DOI of Original Publication



Originally published at

Date of Submission

October 2015


The optical–optical double resonance (OODR) technique is used to investigate the change in magnetic quantum number (M) a state selected molecule undergoes on collision with other molecules. A first linearly polarized dye laser prepares A1Σ+BaO(v = 1) in the J = 1, M = 0 sublevel. The extent of collisional transfer to other M sublevels of both J = 1 and J = 2 is then probed by a second polarized dye laser which induces fluorescence from the C1Σ+ state. Elastic collisions (ΔJ = 0) between BaO (A1Σ+) and CO2 are observed to change M from 0 to ±1 leaving J unchanged. The total elasticM‐changing cross section is σΔM CO2 = 8.4±2.4 Å2. Inelastic collisions (ΔJ = +1’ which transfer molecules to j = 2 also cause M changes. with both Ar and CO2 as collision partners. M, the s p a c ef i x e d projection of J, is found to be neither conserved nor randomized. Quantum atom–diatom collision models with quantization axis along the relative velocity vector are considered. Transition amplitudes in this system are evaluated using the l‐dominant and CS approximations.


Silvers, S. J., Gottscho, R. A., & Field, R. W. Collisional depolarization of state selected (J,M J ) BaO A 1Σ+ measured by optical–optical double resonance. The Journal of Chemical Physics, 74, 6000 (1981). Copyright © 1981 American Institute of Physics.

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