Identification of New Hot Bands in the Blue and Green Band Systems of FeH

✍ Scribed by Catherine Wilson; John M. Brown

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 271 KB
• Volume: 197
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1999.7924

✦ Synopsis

A particularly rich region of the electronic spectrum of FeH from 525 to 545 nm was investigated using the techniques of dispersed and undispersed laser-induced fluorescence. Analysis has led to the discovery that several different electronic transitions are embedded in this region; the (0, 0) and (1, 1) bands of the e 6 ⌸-a 6 ⌬ (green) system, the (0, 2) band of the g 6 ⌽-X 4 ⌬ (intercombination) system, the (0, 1) band of the g 6 ⌽-a 6 ⌬ (blue) system, and the (0, 0) band of the g 6 ⌽-b 6 ⌸ system. Seventy-five lines were assigned in the (0, 1) band of the g 6 ⌽-a 6 ⌬ transition. These, with the assignment of an additional 14 lines in the 583 nm region to the (0, 1) band of the e 6 ⌸-a 6 ⌬ transition, led to the extension of the known term values to higher J values for the ⍀ ϭ 9/2, 7/2, and 5/2 spin components of the v ϭ 1 level of the a 6 ⌬ state and the novel characterization of the a 6 ⌬ 3/ 2 (v ϭ 1) and g 6 ⌽ 5/ 2 (v ϭ 0) components. A further 73 lines were assigned to the first four subbands of the (1, 1) band of the e 6 ⌸-a 6 ⌬ transition and term values for the lowest four spin components of the v ϭ 1 level of the e 6 ⌸ state were determined. This provides the first experimental measurement of a vibrational interval in one of the higher lying electronic states of FeH. The interval does not appear to vary strongly between the spin components (⌬G 1/ 2 ϭ 1717, 1713, 1710 cm Ϫ1 for ⍀ ϭ 7/2, 5/2, 3/2, respectively). Remarkably few of the hot-band transitions assigned in this work could be identified in the complex, high-temperature spectrum of FeH recorded by P. McCormack and S. O'Connor [Astron.