Study of the B″B¯Σu+1 state of H2: Transition probabilities from the ground state, dissociative widths, and Fano parameters

Abstract

The transition probabilities, the dissociation widths, and the associated Fano parameters for rovibronic lines with J"=0,...,3 of the absorption bands of the B"B 1Sigmau+ state out of the X 1Sigmag+ v"=0 ground state were measured over the complete vibrational progression, showing clearly that only the inner-well state with B" 4psigma character can absorb vuv light and predissociate efficiently. The absolute values of these transition probablities, predissociation widths, and Fano parameters were found to agree well with ab initio calculations if one takes into account that the calculations neglect nonadiabatic couplings.

VUV Spectroscopic Study of theD1ΠuState of Molecular Deuterium

“…In order to evaluate the importance of the continua, certain points have been recorded without gas at the beginning and at the end of the scanning procedure. The sources of uncertainty in the absolute cross-section measurements (length, pressure and temperature) are estimated to a total error of 6%, which has to be added to the statistical error due to the noise at each recorded point [24]. The Ly-α and ion detection efficiencies depend on the geometry and the detectors used, but are independent of the wavelength.…”

“…from one level to the other. Quantitative information on the fluorescence cross sections is obtained by subtracting the dissociation and ionization spectra from the absorption spectrum [24] σ f luo = σ dif = σ abs − σ diss − σ ion (8) and is referred to as the difference spectrum. The D 1 Π − u levels radiate and therefore appear in the fluorescence spectrum, which is less congested and has a better signal to noise ratio than the absorption spectrum.…”

“…The potential energy curves [29] for the aforementioned electronic states are illustrated in Fig. 3 along with the curve of the B ′′B1 Σ + u state [30], which is also predissociated due to a coupling to the B ′ state [24].…”

“…This model, originally developed by Jungen and Atabek [22], was recently worked out in detail to interpret intensities for Q-branch lines in the D − X system of H 2 and D 2 [23][24][25]. Subsequently this model was used to interpret the competing decay channels (fluorescence, dissociation and ionization) in the [19,20].…”

Spectroscopic observation of bound ungerade ion-pair states in molecular hydrogen

“…The unusual structure and dynamics of these molecular configurations have long been of interest; however, these same attributes have also made them difficult to study [8][9][10][11]. In particular, the ion-pair configuration has yet to be fully explored in molecular hydrogen.…”