High resolution vacuum ultraviolet emission spectrum of D2: The B′Σu+1→XΣg+1 band system

Abstract

In this work, we have extended our previous high resolution study of the vacuum ultraviolet emission spectrum of the D2 molecule [M. Roudjane, et al. J. Chem. Phys. 125, 214305 (2006)] up to 124.2 nm in order to investigate the B' 1Sigmau+-->X 1Sigmag+ band system. The analysis of the spectrum has been carried out by means of a complex spectrum visual identification code IDEN [V. I. Azarov, Phys. Scr. 44, 528 (1991); 48, 656, (1993)] and supported by theoretical calculations using ab initio data [L. Wolniewicz, J. Chem. Phys. 103, 1792 (1995); 99, 1851 (1993); G. Staszewska and L. Wolniewicz, J. Mol. Spectrosc. 212, 208 (2002); L. Wolniewicz and G. Staszewska, 220, 45 (2003)] which provided level energies and transition probabilities. More than 1480 new emission lines have been observed and 109 bands belonging to the B' 1Sigmau+-->X 1Sigmag+ system have been identified between 84.1 and 121.6 nm. Except for the upsilon'-0 bands that were reported in absorption [I. Dabrowski and G. Herzberg, Can. J. Phys. 52, 1110 (1974)], all the upsilon'-upsilon" bands are reported here for the first time. The analysis led to the determination of 111 rovibronic energy levels in the B' 1Sigmau+ state, of which 31 with higher rotational numbers J are new. Observed perturbations are accounted for through a set of coupled equations involving the four excited electronic states B 1Sigmau+, B' 1Sigmau+, C 1Piu, and D 1Piu and including nonadiabatic couplings. The solution of this set provides the percent contribution of these four states to each of the observed rovibronic level.

Optimal values of rovibronic energy levels for triplet electronic states of molecular deuterium

“…In our opinion, the assignments found in [19,20] also should be confirmed by the appropriate statistical analysis of all available in literature experimental data on the wavenumbers for all other singlet band systems of D 2 . For that purpose it is possible to use the approach proposed and realized in our papers [8,9,23,24].…”

“…Although the approach seems to be a rather powerful and prospective tool for finding new assignments in the spectra of hydrogen isotopomers, the final results of [19,20] can not be considered as optimal values of the rovibronic energy levels for the D 1 Π u , D ′1 Π u , and B ′1 Σ u electronic states studied in [19,20]. They were simply calculated as the average of values derived from different observed line wavenumbers added to the corresponding lower vibro-rotational levels of the X 1 Σ + g ground electronic state from [14], assumed to be known with negligible uncertainty.…”

“…Recently in [19,20], the identification of rovibronic lines of three singlet VUV band systems of D 2 has been obtained by common use of semi-empiric calculations (of the levels and the transition probabilities) together with the program IDEN [21,22] developed for visual identification of complex atomic spectra. Although the approach seems to be a rather powerful and prospective tool for finding new assignments in the spectra of hydrogen isotopomers, the final results of [19,20] can not be considered as optimal values of the rovibronic energy levels for the D 1 Π u , D ′1 Π u , and B ′1 Σ u electronic states studied in [19,20].…”

VUV Fourier-transform absorption study of the Lyman and Werner bands in D2

“…19 Over the years the accuracy has been further improved resulting in a highly accurate laser study by Roudjane et al, 20 focusing on a low number of bands, which may be used for calibration purposes of subsequent studies, including the present one. The most accurate comprehensive investigations of the D 2 spectrum were conducted by Abgrall et al 21 and Roudjane et al, 22,23 both in emission and with spectrographs of 3 m and 10 m, respectively. Another extensive study is based on the emission data by Dieke's laboratory group, collected over 30 years starting in the early 1930s.…”

Extreme ultraviolet laser calibration of D_2Lyman and Werner transitions

“…Since a similar procedure was also used by Dabrowski and Herzberg [2] for calibration of their D 2 spectrum, a systematic shift of their data with respect to the present laser-based results may have the same origin. A second comparison is made between the observed transition frequencies and calculations based on the theoretical framework as presented in [7,8] [2], and will be used, together with the highly accurate XUV measurements on H 2 [19], as calibration lines for VUV emission studies, in particular for the D 2 and HD molecules. …”