Excitationof the lowest autoionizingnp5(n+1)s2, 2P3/2,1/2states of Na(n = 2), K(n = 3), Rb(n = 4) andCs(n = 5) byelectron impact

Abstract

Relativistic distorted-wave (RDW) calculations are carried out for the electron impact excitation of the lowest autoionizing states np5(n+1)s2, 2P3/2,1/2 in Na(n = 2), K(n = 3), Rb(n = 4) and Cs(n = 5) alkali atoms from the ground np6(n+1)s, 2S1/2 state. Detailed results in the range of near threshold to 1.5 keV incident electron energies are obtained for total cross sections of the magnetic substates of the individual 2P3/2 and 2P1/2 states. Utilizing these, the results are presented for their total cross sections, alignment parameter 20 of the 2P3/2 state and the intensity of the ejected electrons from the 2P3/2 state. RDW calculations excluding the exchange effect and relativistic Born approximation calculations are also performed for comparison. The results are compared and discussed in the light of earlier available results and the recently reported experimental data from the Freiburg group (Germany).