Lambda doublet

Thermal distributions of NO(u 2, J, A Ej,) states were observed, wherein the population in any level was determined by the internal energy and the parameter Tr. and independent of spin-orbit state or lambda doublet species. This is in contrast to the rotational rainbows, the propensities for preferential population in the Il(A ) lambda doublet species and the Fj spin orbit state which were observed in direct inelastic scattering of NO/Ag(l 11). 

Calculations by Corey et al. (CSAL) implicated electron orbital effects as the source of the molecular alignment. In the experiment by Jacobs, both lambda doublets exhibited the same degree of alignment therefore, this same mechanism cannot be dominant. 

The rotational population distributions were Boltzmann in nature, characterized by 7Ji = 640 35 K. This seems substantially lower than yet somewhat larger than the temperature associated with the translational degree of freedom. The lambda doublet species were statistically populated. The population ratio of i =l/t =0 was roughly 0.09, consistent with a vibrational temperature Ty— 1120 35K. The same rotational and spin-orbit distributions were obtained for molecules desorbed in t = 1 as for f = 0 levels. Finally, there was no dependence in the J-state distributions on desorption angle. 

Moonbong-Yang, Alexander MH (1995) Ab initio potential energy surfaces and quantum scattering studies of NO(X2 n) with He Lambda-doublet resolved rotational and electronic fine-structure transitions. J Chem Phys 103 6973-6983... 

A.I.Burshtein and E.E.Nikitin, Line shape of transition between lambda-doublet components, Zhum.Eksp.Teor.Fiz. 55, 1401 (1968)... 

The labels + and - refer to the parity of the rotational level times (-l/. Lambda doublets not resolved. 

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