Positron Impact Excitation of the nS States of Atomic Hydrogen

Abstract

The excitation cross sections of the nS states, n = 2 to 6, of atomic hydrogen at various incident positron energies (10.23 to 300 eV) were calculated using the variational polarized-orbital method. Nine partial waves were used to obtain converged cross sections. The present results should be useful for comparison with results obtained from other theories and approximations. The positron-impact cross section was found to be higher than the electron-impact cross sections. Experimental and other theoretical results are discussed. The threshold law of excitation is discussed and the cross sections in this region were seen to obey the threshold law proportional to (ln k f ) −2 . Cross sections were calculated in the Born approximation also and compared to those obtained using the variational polarized orbital method.

Positron Impact Excitation of the nS, nP, and nD States of Atomic Hydrogen

“…In Table 2, we give results for elastic and excitation cross sections. Excitation cross sections for the S states are taken from [11,12]. The maximum of excitation cross sections is at k=1.40.…”

“…We carried out such calculations of the nS states, n being 2 to 6, using the distorted wave approximation [11,12]. Equations (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) in reference [11] give the formulation of these calculations.…”

“…We carried out such calculations of the nS states, n being 2 to 6, using the distorted wave approximation [11,12]. Equations (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) in reference [11] give the formulation of these calculations. In the above mentioned calculations [5,6,11,12], we used the hybrid theory [13] to calculate scattering functions.…”

“…Equations (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) in reference [11] give the formulation of these calculations. In the above mentioned calculations [5,6,11,12], we used the hybrid theory [13] to calculate scattering functions. In this approach, the long-range and short-range correlations are taken into account at the same time and the theory is variationally correct.…”