Resonances in H^-associated with the n=2, 3 and 4 hydrogenic thresholds

Abstract

The energies and widths of resonances in the scattering of electrons by hydrogen atoms are calculated for incident electron energies from 0.686 to 0.9374 Ryd using a fifteen-state R-matrix calculation. The results are compared with available experimental data and theoretical calculations. The arrangement of these resonances in series converging to the n = 2, 3 and 4 thresholds is also studied.

Shape resonances ine−-H scattering above the hydrogenN=4 threshold

“…and an R-matrix calculation [9]. Other methods to investigate this shape resonance include the group theoretical approach [10,11], the use of hyperspherical coordinates [12,13], and the method of complex-coordinate rotation [14,15].…”

Observation of the partial decay intoH0(n’=2) by excitedH−Halka1, Bryant2, MacKerrow3 et al. 1991Phys. Rev. A395190View full textAdd to dashboardCite

“…We have made the first step toward a quantitative study of these ratios by observing the cross section for both the H *'(3) and H "(4) decaying into H (2) as depicted in Figs. 1 [16], 12.6470 [20] 0.0325 [17], 0.0316 [18], 0.0325 [20] 13.3448 [14], 13.3502 [15], 13.3435 [16], 13.3422 [21] 0.0275 [18], 0.0339 [19], 0.0367 [21] 12. Feshbach peak whose energy is weI1 known from experiment [11].…”

15-stateR-matrix investigation of resonances in elastic scattering of electrons from atomic hydrogen at low energies

“…A numerical table of the results by energies at 30', 55, 70', and 90' can be obtained on request from the authors [22]. e +H(ls)~e +H(ls) (9) The 15-state R-matrix calculations of Pathak and coworkers [13,14] and Fon, Aggarwal, and Ratnavelu [21] have been extended to obtain the differential cross sections and the spin asymmetry A "&, (O, k ) for the transition A. Elastic difFerential cross sections and the A &, |, (90', k ) parameter as functions of energies Figure 2 compares the three-state CC approximation [8,9] and the 15-state R-matrix calculation on elastic differential cross sections and A ""(90, k ) with the ex- [7], and Fletcher et al [5]). In Fig.…”

“…In this paper, the 15-state R-matrix calculations of Pathak and co-workers [13,14] have been extended to calculate the elastic differential cross sections and the spin asymmetry in the elastic scattering of spin-polarized electrons by spin-polarized atoms. The aims of this paper are (i) to probe the sensitivity of the A i, i, (O, k ) parameter in response to the presence of resonances; (ii) to reconfirm the observation of resonances reported by Warner, Rutter, and King [11];(iii) to carry out convergence studies on the close-coupling expansion in the calculation of elastic differential cross sections and the spin asymmetry.…”

“…The R-matrix method for electron-atom collisions has been discussed in detail (see Burke, Hibbert, and Robb [IS] and Berrington et al [16]). The target wave functions, energy levels, and scattering wave functions used in the present 15-state R-matrix calculation have been fully described by Pathak, Kingston, and Berrington [13] and Aggarwal et al [17]. However, to recapitulate, the wave function describing the two-electron scattering system can be expanded as mnk (2L +3)(2L + 1)(2L -1) (2) where N, are the channel functions formed from the target states of the hydrogen atom, uJ are the radial basis functions describing the motion of the scattered electron (the continuum orbitals), and (t/, are the two-electron functions (the bound-bound orbitals) which allow for short-range correlation effects.…”