Analysis of autoionizing Rydberg states in the vacuum ultraviolet absorption spectrum of HBr and DBr

Angle- and spin-resolved photoelectron spectroscopy of thepπ outer valence shell of HBr molecules

“…The relative photoelectron intensities for photon energies below and above the threshold of the HBr ÷ A2S + excited state (EIp = 15.296 eV [29]) are shown in Fig The results of the least squares fit are given for A (0) ( ) and for…”

“…As seen from Figs. 3 and 4, the experimentally determined parameters exhibit a different behavior in the spin-orbit autoionization region in comparison with the energy region between the Zir/1/z threshold at Ephoton = 12.0 eV and the first 5 p(a, re) Rydberg state with a AZr + core at Ephoton = 12.83 eV [29]. In region (I) the obtained A and ~ parameters have small values, ~ is close to zero and fi is large.…”

“…Comparisons of the spin polarization data for region (I) of HBr (dominated by resonances with a (4pro) 3 2H1/2 ionic core) and for the results for the corresponding nd(r~, 6) spin-orbit Rydberg states of HI [13] (with a (5Uc) 3 2111/2 ionic core), obtained with high energy resolution produced by frequency-converted laser radiation, indicate a similar behavior of the photoionization parameters in this energy region with A values ranging from 0.06 to 0.1,, values from 0.15 to 0.21 and values close to zero. In the energy region of electronic autoionization (II) the dynamical photoionization parameters reveal pronounced resonance structures induced by vibrational series of Rydberg states converging to the A2S + and to the repulsive a4H ionic states [10,26] leading to an oscillatory pattern of the cross section [10,11,29,32]. The remarkable decrease of the parameters A and ~ to small values in the photon energy region of the partially dissociated 4da 1S+ resonances between the 5p(a, ~) ~H and the 5d~z ~1I Rydberg states, with values close to zero at the threshold of the 4drc 1H Rydberg state at Ephoton = 13.43eV, illustrates the strong influence of autoionization and predissociation on the photoionization process [10,11,29].…”

“…In the energy region of electronic autoionization (II) the dynamical photoionization parameters reveal pronounced resonance structures induced by vibrational series of Rydberg states converging to the A2S + and to the repulsive a4H ionic states [10,26] leading to an oscillatory pattern of the cross section [10,11,29,32]. The remarkable decrease of the parameters A and ~ to small values in the photon energy region of the partially dissociated 4da 1S+ resonances between the 5p(a, ~) ~H and the 5d~z ~1I Rydberg states, with values close to zero at the threshold of the 4drc 1H Rydberg state at Ephoton = 13.43eV, illustrates the strong influence of autoionization and predissociation on the photoionization process [10,11,29]. An additional indication of these influences is the change of the sign of the/3 parameter and the increase of e. Except for the results for the parameter ~, the energy dependencies for the dynamical parameters in the photon energy region from 12.7 eV to 14.7 eV were presented and discussed in detail before [11].…”

Autoionization and neutral dissociation of superexcited HI studied by two-dimensional photoelectron spectroscopy

“…As for HCl and HBr, series of Rydberg states converging to the ionic à 2 ⌺ 1/2 ϩ states appear as extensive vibrational progressions on photoabsorption, photoionization, and fluorescence cross sections. [1][2][3][4][5][6][7][8][9] These cross sections for the vibrational levels show evidence of competition in decay of the Rydberg states between autoionization and predissociation. Characters of the involving states and branching ratios have been well accounted for by theoretical calculations.…”