Astrophysically Useful Parameters for Some Vibronic Transitions of AlH and BH

Abstract

For molecular identification in astrophysical sources, an astrophysicist needs some spectroscopic parameters such as dissociation energy, vibrational or rotational temperature of the source, band or line wavelengths, transition probability parameters, etc. The Franck-Condon(FC) factors are proportional to the transition probabilities. In this study, the FC factors and r-centroids for the vibronic (vibration-electronic) transitions C 1 + → X 1 + of aluminium hydride (AlH), b 3 (−) → a 3 , C 1 + → A 1 & C 1 → 1 of boron hydride (BH) have been evaluated and the results are presented in tables which include band origin/head wavelengths. The physical & astrophysical significances of our evaluated FC factors & r-centroids have been discussed and the possible presence of AlH in sunspot umbral spectra is also predicted.

On the search for BF, BH and BS molecular lines in sunspot spectra

“…This ensures that the identifications are not based on chance coincidences and are quite satisfactory. However, additional support to the identifications come from the overall redward or blueward degradations of the intensities in the rotational lines of the P, Q, and R branches [8,24], as compared with the results of relative line strengths 11619.73 P R (8) 11622.09 P R (9) 11624.41 P R (10) 11626.56 B R (11) 11628.63 P R (12) 11630.66 P R (16) 11637.76 P R (17) 11639.29 P R (18) 11640.75 P R (19) 11642.11 P R (20) 11643.42 P R (21) 11644.61 S R (22) 11645.76 P R (23) 11646.89 P R (24) 11647.91 P R (27) 11650.48 P R (30) 11652.58 P reported from rotational analysis. We have examined this aspect and find the agreement to be convincing.…”

“…(29) 17649.44 S Q 1 (11) 17849.12 P Q 1 (34) 17660.03 P R 12 (11) 17849.20 B R 12 (34) 17660.46 S R 1 (15) 17850.55 S P 12 (28) 17662.35 S Q 1 (9) 17855.86 P Q 1 (33) 17672.46 B R 12 (9) 17855.86 P R 12 (33) 17672.90 B P 1 (5) 17858.06 P P 12 (27) 17674.83 B Q 12 (5) 17858.06 P P 1 (29) 17683.14 S R 1 (13) 17858.06 P Q 1 (32) 17684. (31) 17696.59 P Q 12 (3) 17863.09 P Q 1 (30) 17707.51 S Q 1 (6) 17863.25 B R 12 (30) 17707.93 P R 12 (6) 17863.25 B P 12 (24) 17710.01 S R 1 (11) 17864.03 P R 1 (33) 17713.65 P Q 1 (4) 17866.26 P Q 12 (26) 17717.47 P R 12 (4) 17866.26 P Q 1 (29) 17718.41 P Q 1 (3) 17867.25 P (25) 17728.04 P Q 1 (2) 17867.97 P Q 1 (28) 17728.97 P R 12 (2) 17867.97 P R 12 (28) 17729.31 B R 1 (9) 17868.45 B P 12 (22) 17731.59 P R 1 (1) 17871.45 B P 1 (24) 17737.86 P R 1 (7) 17871.45 B Q 12 (24) 17738.21 P R 1 (2) 17872.30 P P 12 (21) 17741.79 P R 1 (6) 17872.30 P R 1 (30) 17745.14 P R 1 (4) 17872.95 P Note: N -number of laboratory lines, w -line density in sunspot umbral spectrum, C -number of chance coincidences, PE -probable error corresponding to C, Inumber of identified lines called I-parameter. Note: N -number of laboratory lin...…”

“…It is better to mention here that the errors in rotational temperatures may probably due to the severe blending of identified (23) 15861.03 14.9 R 12 (21) 17792.14 15.1 P 12 (19) 15872. 22 11.4 P 12 (15) 17794.96 15.4 P 12 (13) 15918.57 17.1 P 1 (11) 17835.22 5.8 P 1 (15) 15921.91 12.6 R 12 (13) 17840.87 6.9 R 1 (16) 17846.22 9.1 R 1 (4) 17872.95 6.1…”

“…The possible presence of BS was suspected by Karthikeyan et al [12]. The transition probability parameters like Franck-Condon (FC) factors and r-centroids for certain band systems of BF, BH and BS were reported by Raja and Rajamanickam [17] and Karthikeyan et al [11,12]. The significant values of transition probability parameters reported by these authors for BF, BH and BS molecules and the suspected presence of BF and BH molecules suggested by the observations of Wohl [32], called for a fresh search for the presence of these molecular lines in umbral spectra.…”

TERAHERTZ SPECTROSCOPY OF CrH (X 6Σ+) AND AlH (X 1Σ+)

“…AlO has also been found in stellar photospheres, such as those of o Ceti and VY CMa, both in absorption and emission via its electronic transitions (e.g., Kamiński et al 2016). More importantly, AlH itself has also been observed optically in the photospheres of both M-and S-type stars, including χ Cygni in emission, and possibly in sunspots in absorption (e.g., Herbig 1956; Karthikeyan et al 2006). Both CrH and AlH have been investigated extensively in the laboratory at infrared and optical wavelengths (see Harrison et al 2006 andZiurys 2014, respectively, for reviews of these data).…”