Quantal and semiclassical calculations of charge transfer cross sections in + H collisions for impact energies of

Abstract

Total and n-partial cross sections for charge transfer in Be 4+ + H(1s, 2s) collisions are calculated for collision energies between 2.5 eV amu −1 and 25 keV amu −1 . A molecular expansion is employed, and semiclassical and quantal calculations are carried out including a common translation factor and a common reaction coordinate, respectively. The comparison between quantal and semiclassical cross sections and transition probabilities is discussed.

Atomic-Orbital Close-Coupling Calculations Of Electron Capture From Hydrogen Atoms Into Highly Excited Rydberg States Of Multiply Charged Ions

“…Our data [3] for the H(1s) target show very good agreement with data calculated by Minami et al in the lattice time-dependent Schrödinger equation (LTDSE) approach [7], classical trajectory Monte Carlo (CTMC) cross sections from Illescas and Riera [8], and recommended cross sections for C 4+ ions from Janev et al [9]. In the case of the H(n=2) target, CTMC cross section from Errea et al [10], LandauZener data from Casaubon [11], and another set of CTMC calculations from Hoekstra et al [12] are shown in Fig.1a for comparison. In this case the agreement is not as excellent as in the H(1s) case, but is nevertheless quite satisfactory.…”

“…Cross Section [10 1. Total charge exchange cross sections for (a) Be 4+ + H(1s) in comparison with data from [7], [8], [9] and for (b) Be 4+ + H(n=2) in comparison with data from [10], [11], [12]. A more elaborate analysis of these results can be found in [3].…”

Application of a grid numerical method to calculate state-selective cross sections for electron capture inBe4++H(1s)collisions

“…In this table, the MOCC (18) calculations employ a minimal 18-term basis set that includes the molecular channels dissociating into Be 3+ (n = 3,4), and MOCC (88, 96) are the two extended bases of Refs. [15,16]. Since both MOCC and AOCC computational procedures are very different, the agreement indicates that the absolute uncertainties of these cross sections are smaller than ±10 −17 cm 2 .…”

“…The application of the CXRS diagnostics requires the knowledge of state-resolved EC cross sections (1), which are in general difficult to measure, and, in particular, only theoretical data are available for collisions involving Be q+ ions. The relevance of EC in fusion research has motivated many works [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] applying very different methods, but despite the apparent simplicity of monoelectronic systems, significant discrepancies remain between the results. While close-coupling and distorted-wave methods are very accurate in the low (E < 25 keV/u) and high (E > 1000 keV/u) energy range, respectively, the cross sections for the high-n capture levels are far from been converged in the intermediate energy domain that characterizes the probe beam.…”

“…The validity of the eikonal approximation for the collision (2) has been discussed in Ref. [15] by comparing eikonal and full quantum mechanical calculations. This comparison at E = 250 eV/u shows that the differences for the total EC cross section and for the n = 3 partial cross section are on the order of 1%, and on the order of 5% for the partial cross section for populating the level Be 3+ (n = 4).…”