A theoretical analysis of the state-specific decomposition of OH(A 2Σ+,v′,N′,F1/F2) levels, including the effects of spin–orbit and Coriolis interactions

Abstract

The state-specific decomposition OH(A 2Σ+,v′,N′,F1/F2)→O(3PJ)+H(2S) is investigated using multichannel scattering theory based on potential energy curves, spin–orbit couplings, and Coriolis couplings, obtained from multireference configuration interaction wave functions. The fine-structure branching fractions of the O(3PJ) fragment are determined and compared with the results of frequently used approximate models. The predissociation rates of the individual OH(A 2Σ+,v′,N′,F1/F2) levels are also computed and compared with the results of recent experiments.

Rate Constants for Fine-structure Excitations in O–H Collisions with Error Bars Obtained by Machine Learning

“…These temperature dependences are obtained from the GP model. As an additional check of the accuracy of these results, we computed the rate constants with the coupled channel approach using the potentials of Parlant and Yarkony (1999). The results, shown by blue triangles in Figure 3, are graphically indistinguishable from the means of the uncertainty intervals represented by the red solid lines.…”

“…These potentials have been computed most recently by Parlant and Yarkony (1999). Figure 1 shows the calculations of Parlant and Yarkony (1999) as symbols. Instead of using the fixed interaction potentials for the quantum scattering calculations as was done by all previous authors, in the present work we ask the following question: if each of the potentials is uncertain to within a grey band shown in Figure 1, what is the corresponding uncertainty in the collision rates?…”

“…In order to account for the variation of the potentials, we first produce the analytical fits of the numerical data of Parlant and Yarkony (1999) shown in Figure 1 as solid curves. We then modulate each of the analytical fits of the repulsive potentials for the excited molecular states 2 Σ, 4 Π and 4 Σ by a scaling factor varied from 0.8 to 1.2.…”

“…As we will show below, adapting the potentials to the collision problem (1) resulted in an error, rendering the calculations of Abrahamsson et al (2007) inaccurate. In addition, the interaction potentials of Parlant & Yarkony (1999), as any intermolecular potentials, are subject to uncertainties associated with errors of the ab initio calculations. It is important to evaluate the effect of these uncertainties on the rate constants.…”

“…These potentials have been computed most recently by Parlant and Yarkony (1999). Figure 1 shows the calculations of Parlant and Yarkony (1999) as symbols.…”