Excitation of autoionizing states in potassium by electron impact

Abstract

The ejected-electron excitation functions for the 3p 5 3d4s 4 P 3/2 , 4 D J lowest quartet and 3p 5 3d4s(1 P) 2 P 3/2 upper doublet autoionizing states in potassium have been measured with an energy resolution of 0.2 eV over the electron impact energy region from the lowest excitation threshold up to 500 eV. The detailed picture of the excitation dynamics of the 4 P 3/2 , 4 D j and 2 P 3/2 levels in the near-threshold impact energy region has been achieved due to the use of a small increment of the incident electron energy. An analysis of the data, including the consideration of resonance and cascade excitation processes, has been performed on the base of available experimental and theoretical data on the 3p 6-excitation in potassium atoms.

Radiative transitions between lowest autoionizing states in sodium

“…In ejected-electron excitation functions for the lowest 2p 5 3s 2 2 P 3/2 and 2 P 1/2 autoionizing states in sodium [1], a strong resonance structure was revealed in the impact energy regions of 32-33 and 36.5-40.0 eV. However, recent R-matrix (close-coupling) calculations [2] did not confirm the existence of negative ion resonances at these energies.…”

“…In (1), N 1 and N 0 are the population densities of the levels 2p 5 3s3p LSJ and 2p 6 3s 2 S 1/2 , respectively, N e and v are the density and velocity of exciting electrons, σ 01 and σ 02 are the excitation crosssections from the ground states to the 2p 5 3s 2 2 P J0 and 2p 5 3s3p LSJ levels, respectively, A 10 and A a 1 are radiative and autoionization probabilities from the states 2p 5 3s 2 2 P J0 , respectively, and γ 21 is the fluorescence yield of the transition 2p 5 3s3p LSJ → 2p 5 3s 2 2 P J0 . The cross-sections for the excitation 2p 6 3s 2 S 1/2 → 2p 5 3s 2 2 P J0 are investigated both experimentally (e. g. [1,38]) and theoretically [38]. The excitation crosssections of the states 2p 5 3s3p LSJ were calculated in the present work by applying DW with exchange approximation.…”

“…The absorption spectrum was registered by Wolf et al [4], Connerade et al [5], Sugar et al [6], and Baig et al [7]. The ejected-electron spectra were also studied by different experimental methods [1,[8][9][10]. The radiative decay of the 2p 5 3s3p autoionizing states was studied by Zhmenjak et al [11] in electron-atom collisions.…”

“…For the investigation of core-excited autoionizing states of Na, a number of experimental [1,[4][5][6][7][8][9][10][11] and theoretical [12,13] works was devoted. The absorption spectrum was registered by Wolf et al [4], Connerade et al [5], Sugar et al [6], and Baig et al [7].…”