Ionization and excitation in collisions between antiprotons and H(1s) atoms studied with Sturmian bases

Abstract

Coupled two-center as well as one-center Sturmian cross sections have been determined for ionization and excitation inp-H(1s) collisions atp energies from 1 to 16 000 keV, following the author's recent work for p-H(1s) collisions [Phys. Rev. A 80, 032701 (2009)]. Basis convergence is studied in detail. Results for ionization and excitation are compared to other coupled-state results and to numerical results, as well as limited experimental results for ionization only. Except for the large, two-center coupled-Gaussian-pseudostate calculation of Toshima for ionization only [Phys. Rev. A 64, 024701 (2001)], previous calculations employed one-center bases, including a one-center Sturmian calculation by Igarashi et al. [Phys. Rev. A 61, 062712 (2000)]. A strong contrast with p-H collisions is confirmed at intermediate energies, while at high energies the extent of agreement is revealed between coupled-state results for the two collisional systems, as well as with first Born results.

Current status of antiproton impact ionization of atoms and molecules: theoretical and experimental perspectives

“…Note added in proof. While this paper was in the process of being reviewed new coupled-channel calculations were published for the antiproton-atomic hydrogen system by Winter [180], the results of which are in line with the discussion of section 5.1.…”

Antiproton-impact ionization of H, He and Li

“…As a convergence check, additional calculations at 10 keV, using a 384-point radial mesh with r = 0.20 and only 16 lm (l = 0-3) coupled channels, yielded a cross section less than 1% different from the finer mesh and more coupled channel calculations. [4]; dashed (blue) curve: CCIE calculations [16]; dot-dashed (purple) curve: CTCS calculations [17]; solid (green) circles with error bars: experiment [15] (1.0 Mb = 1.0 × 10 −18 cm 2 ). TDCC-3D cross-section results are presented in figure 1 and compared with a LEAR/CERN experiment [15] and time-dependent Schrodinger equation [4], coupledchannel integral equation (CCIE) [16] and coupled two-centre Sturmian (CTCS) [17] calculations.…”

“…[4]; dashed (blue) curve: CCIE calculations [16]; dot-dashed (purple) curve: CTCS calculations [17]; solid (green) circles with error bars: experiment [15] (1.0 Mb = 1.0 × 10 −18 cm 2 ). TDCC-3D cross-section results are presented in figure 1 and compared with a LEAR/CERN experiment [15] and time-dependent Schrodinger equation [4], coupledchannel integral equation (CCIE) [16] and coupled two-centre Sturmian (CTCS) [17] calculations. Although the error bars are large, the LEAR/CERN measurements are somewhat lower than all of the calculations, except near 100 keV.…”

“…In this paper, we use the TDCC-3D method to calculate antiprotonimpact single-ionization cross sections for H, He and Li over an incident energy range from 1.0 to 100.0 keV. For H, we compare results with an experiment [15] using the low-energy antiproton ring (LEAR) at CERN and with the time-dependent Schrodinger equation [4], coupled-channel integral equation [16] and coupled two-centre Sturmian [17] calculations. For He, we compare results with LEAR [18] and AD [19] experiments at CERN, with present TDCC-6D calculations, with previous TDCC-6D calculations [12] and with time-dependent finite-element calculations [13].…”

“…Figure 1.Antiproton-impact single ionization of H. Striped (red) squares: TDCC-3D calculations; solid (red) squares: time-dependent Schrodinger equation calculations[4]; dashed (blue) curve: CCIE calculations[16]; dot-dashed (purple) curve: CTCS calculations[17]; solid (green) circles with error bars: experiment[15] (1.0 Mb = 1.0 × 10 −18 cm 2 ).…”