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Comparison of Semiempirical and ab initio Absolute Probabilities of Rovibronic Transitions for the I1Πg -, J 1Δg - → C1Π u ± System of Bands of the H2 Molecule. / Astashkevich, S. A.; Lavrov, B. P.
в: Optics and Spectroscopy (English translation of Optika i Spektroskopiya), Том 88, № 5, 01.05.2000, стр. 676-685.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Comparison of Semiempirical and ab initio Absolute Probabilities of Rovibronic Transitions for the I1Πg -, J 1Δg - → C1Π u ± System of Bands of the H2 Molecule
AU - Astashkevich, S. A.
AU - Lavrov, B. P.
PY - 2000/5/1
Y1 - 2000/5/1
N2 - The absolute values of probabilities of the I1Π g -, v′, J′; J1 Δ g -, v′, J′ → C1Π u ±, v″, J″ spontaneous transitions in the H2 molecule (for the vibrational and rotational quantum numbers v′ = v″ = 0-3, J′ = 1-6, and J″ = J′, J′ ± 1) are calculated by using ab initio and semiempirical data on the dipole moments of the 3dπ-Πg, 3dδ1 Δg → 2pπ1Πu electronic transitions. In both cases, the calculations are performed both in the adiabatic approximation and with an allowance for the nonadiabatic effect of electronic-rotational interaction. The coefficients of expansion of the wave functions of perturbed rovibrpnic states in the Born-Oppenheimer basis functions used in the calculations were obtained in the approximation of pure precession from experimental values of the terms. It was found that the values of transition probabilities based on the ab initio calculations systematically exceed the corresponding semiempirical data by a factor of 1.2-1.9 for the I1Πg → C1Πu ± Transition and by a factor of 1.4-1.6 for the J1 Δg - → C1Πu ± transition. It was established that the difference between the ab initio and semiempirical values of electronic transition moments virtually has no effect on the dependence of the transition probabilities on the vibrational quantum numbers. The discrepancies between the results of adiabatic and nonadiabatic calculations are significant and reach two orders of magnitude, which is indicative of the important role of perturbations in the probabilities of the transitions considered.
AB - The absolute values of probabilities of the I1Π g -, v′, J′; J1 Δ g -, v′, J′ → C1Π u ±, v″, J″ spontaneous transitions in the H2 molecule (for the vibrational and rotational quantum numbers v′ = v″ = 0-3, J′ = 1-6, and J″ = J′, J′ ± 1) are calculated by using ab initio and semiempirical data on the dipole moments of the 3dπ-Πg, 3dδ1 Δg → 2pπ1Πu electronic transitions. In both cases, the calculations are performed both in the adiabatic approximation and with an allowance for the nonadiabatic effect of electronic-rotational interaction. The coefficients of expansion of the wave functions of perturbed rovibrpnic states in the Born-Oppenheimer basis functions used in the calculations were obtained in the approximation of pure precession from experimental values of the terms. It was found that the values of transition probabilities based on the ab initio calculations systematically exceed the corresponding semiempirical data by a factor of 1.2-1.9 for the I1Πg → C1Πu ± Transition and by a factor of 1.4-1.6 for the J1 Δg - → C1Πu ± transition. It was established that the difference between the ab initio and semiempirical values of electronic transition moments virtually has no effect on the dependence of the transition probabilities on the vibrational quantum numbers. The discrepancies between the results of adiabatic and nonadiabatic calculations are significant and reach two orders of magnitude, which is indicative of the important role of perturbations in the probabilities of the transitions considered.
UR - http://www.scopus.com/inward/record.url?scp=0141449241&partnerID=8YFLogxK
U2 - 10.1134/1.626859
DO - 10.1134/1.626859
M3 - Article
AN - SCOPUS:0141449241
VL - 88
SP - 676
EP - 685
JO - OPTICS AND SPECTROSCOPY
JF - OPTICS AND SPECTROSCOPY
SN - 0030-400X
IS - 5
ER -
ID: 33268693