科研之友
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摘要
The band strength distribution for the D-2 Sigma(+)nu'-A(2)Pi v" electronic transition of AlO, and the effect of R dependence of the electronic transition moment on the distribution, are studied based on the ab initio band strengths and the Franck-Condon factors (FCFs) for bands with vibrational quantum numbers v' = 0-18 and v" = 0-18. The band strength distribution exhibits a Condon parabola of the bands involving v' = 0-9 and 11 of all the inner-well levels of the D-2 Sigma(+) double potential well. Five unobserved bands calculated among the ten largest band strength bands are found to involve the v' levels near the D-2 Sigma(+) potential barrier top. The effect of the R dependence is examined for the FCF maximum bands in the v"-progressions for v' = 0-9 and 11-18 (excluding v' = 10 of the D-2 Sigma(+) outer-well level) by using the ratio of the band strength to the FCF, both relative to the 0-0 band. Large (small) ratios of value 1.276-1.559 (0.619-0.841) are found for ratio > 1 (ratio < 1) bands with v' = 8, 9 and 11-18. An analysis using a model of transition matrix element shows that the difference between (1) the electronic transition moment in the region represented by the R-centroid for each large ratio band and (2) that for the 0-0 band makes the greatest contribution to the ratio. The R-centroids do not properly represent the important R regions (R < 3.0a(0)) for the small ratio bands with V' = 11-18; a possible explanation is discussed. The results imply that the avoided crossings influence the band strength distribution. The Einstein A coefficients have been evaluated for the D-A bands with v' = 0-9 and 11 and v" = 0-18 from the calculated band strengths and transition energies.
- 出版日期2015-2-15
