The excitedJ=01Σu+levels of D 2 : Measurements and ab initio quantum defect

Abstract

Keywords:Vacuum ultraviolet Fourier-transform spectroscopy Molecular deuterium Analysis by multichannel quantum defect theory a b s t r a c tThe DESIRS beamline of the SOLEIL synchrotron facility, equipped with a vacuum ultraviolet Fouriertransform spectrometer has been used to measure PðN 00 ¼ 1Þ (N À N 00 ¼ À1) absorption transitions of the D 2 molecule. Some 44 P-lines were assigned and their transition frequencies determined up to excitation energies of 134,000 cm À1 above the ground state, thereby extending the earlier work by various authors, and considerably improving the spectral accuracy (<0.1 cm À1 ). The assignments have been aided by first principles multichannel quantum defect theory (MQDT) calculations. These calculations also provide predictions of the autoionization widths of the upper levels which agree well with the observed resonance widths.

Excitation of H2 at large internuclear separation: outer well states and continuum resonances

“…Following a similar procedure as in Ref. [53], the natural linewidth extracted from experimental spectra is 7.5(2.0) cm −1 which is consistent with the calculated width of 6.6 cm −1 in Table 2.…”

Experimental and theoretical study of thenpσ1Σu+(Glass‐Maujean1, Vasserot2, Jungen3 et al. 2016Journal of Molecular SpectroscopySelf Cite

“…The theoretical multichannel quantum defect approach used here reproduces step by step the approach described for H 2 in Ref. [7] and used in the preceding paper [3], with the only difference that the values of the reduced nuclear mass and the Rydberg constant have been adapted to the deuterium molecule. As previously the quantum defects and channel dipole transition moments were extracted from the highly accurate theoretical clamped-nuclei (Born-Oppenheimer) potential energy curves [8] and dipole transition moments [9], so that the input data for our calculations are fully ab initio.…”

“…The absorption spectrum of molecular deuterium has been recorded at room temperature using a 10 m normal-incidence monochromator at BESSY. The measured transition energies have an uncertainty of 1 cm −1 , which is less precise than the Fourier-transform (FT) measurements recorded at SOLEIL [3]. However, by using a monochromator, we are in a position to perform absolute intensity measurements and, by monitoring simultaneously the signals for dissociation, ionization and fluorescence, we also have access to the dissociation, ionization and fluorescence partial cross sections.…”

“…This paper is the fourth in a series [1,2,3] dealing with the photoabsorption spectrum of molecular deuterium. This is a combined experimental and theoretical effort, in which multichannel quantum defect theory, MQDT, is used to interpret spectra taken at the SOLEIL and BESSY synchrotron radiation sources.…”

Isotope dependence of thec3Πu−b3Σ${}_{u}^{+}$ andD1Π${}_{u}^{+}$−B′1Σ${}_{u}^{+}$ predissociation rates of molecular hydrogen

“…Ross and Jungen (1994a, 1994b, 1994c investigations of the triplet structure of H 2 . MQDT has been extensively utilized by Glass-Maujean and coworkers with a great deal of success in the interpretation of H 2 and D 2 high resolution spectral transitions between the X g 1 S + and the singlet-ungerade Rydberg states (Glass-Maujean et al 2012a, 2012b, 2012c, 2013a, 2013b, 2013c, 2015a, 2015b, 2016a, 2016b, Glass-Maujean and Schmoranzer 2018. Glass-Maujean et al (2011b) have also examined the relative accuracy of coupled Schrödinger equations and MQDT methods for H 2 and D 2 .…”