Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10557396 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2005 | 8 Pages |
Abstract
The singlet-triplet transition moments are calculated for the NH radical by multiconfiguration self-consistent field (MCSCF) method with a quadratic response (QR) technique. The band systems in the visible region (b1Σ+âX3Σâ and a1ÎâX3Σâ) of the NH radical are analyzed in comparison with previous ab initio treatments and with the recent experimental data in attempt to solve some discrepancies. The b1Σ+âX3ΣΩâ transition moments ratio for the two spin sublevels Ω = 1 and Ω=0 of the ground state is well reproduced and the radiative lifetime of the b1Σ+ state (Ïb=58âms) is obtained in a good agreement with the experimental value Ïb=53(â13+17)âms. The A3Î âa1Î transition probability is calculated for the first time and found to be in an excellent agreement with the recent optical pumping measurements of the NH radical in a molecular beam, where population transfer from the metastable a1Î state to the ground X3Σâ state is achieved. For the a1ÎâX3Σâ transition some improvement is achieved in comparison with the previous ab initio results, but the calculated radiative lifetime (Ïa=3.9âs) is still much lower than the recent measurement provides (Ïa=12.5âs). The zero field splitting and spin-rotation coupling constants are calculated for the ground state by different methods and advantage of the density functional theory is stressed.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Boris Minaev, Lyudmila Yaschuk, Vitalina Kukueva,