K-shell-ionization cross sections for low-Zelements (11≤Z≤22) by protons in the energy range 0.5–2.5 MeV

Abstract

EC-shell-ionization cross sections for Na, Mg, Al, Si, Cl, K, Ca, and Ti by protons in the energy range 0.5 -2.5 MeV have been measured using thin targets. Measurements have also been performed for thin targets of Fe, Ni, and Cu at a few energies. The energy range of protons for these targets corresponds to the reduced velocity {U1/U2&) range 0.2-1.1, in which the cross sections are very sensitive to the increased binding energy and the Coulomb-deflection effects. The measured ionization cross sections are compared with the predictions of the theory based on the perturbed-stationary-state approach including the Coulomb-deflection, energy-loss, and relativistic corrections. The data have been scaled according to various scaling laws to test the validity of the universal nature of the various Coulomb ionization theories based on the plane-wave Born approximation, the binary-encounter approximation, and the simplified semiclassical approximation model as given by La:gsgaard, Andersen, and Lund [in Proceed ings of the Tenth International Conference on the Physics ofElectronic and Atomic Collisions, edited by G. Watel (North-Holland, Amsterdam, 1978), p. 353]. The measured data have also been compared with the calculations of Montenegro and Siguad [J. Phys. B 18, 299 (1985)] based on the theory of lscr molecular-orbital ionization.

Single and doubleK-shell ionization and electron-transfer cross sections for Fe and Ni bombarded by S ions and Fe by Si ions at 1.25–4.70 MeV/amu

“…[20] for K, Ti, and Br targets bombarded by Cl ions. The ECPSSR calculations, which give a very good agreement with the proton and helium projectiles [19], show large deviations for the heavier ions used in the present case. Below a value of 0.15 for the quantity pre/((leo+) the theory underestimates the data, while above this it overestimates the data.…”

“…These values were found to be constant to within 3%%up over the entire energy range of the incident beam. An average value of a~=0.43(2) and 0.50 (2) [10,19). The figure shows, in a universal representation, all our data on Ti [7] and present data on Fe and Ni targets as well as of Hall data by a factor of 2 in the case of near-symmetric collision systems like S or Si~Ti.…”

“…The data of Tanis et al [20] for Cl on K, Ti, and Br are shown by open diamonds, filled squares, and triangles, respectively. The solid line represents the universal PWBA function [10,19]. The inset shows the ratio R=o, "~/crthe~rr for the present collision systems to bring out the deviations in the measured cross sections from the theory.…”

Exploring the Concept of Aromaticity on Complexes of a Fourfold Benzannulated Cyclopentadienyl Ligand

“…">Paul et al 13, 14, two tables regrouping experimental data published before 1991 (the first table13 has 4300 values and the second one14 has about 184 values). Own compilation, gathering the data published from 1992 to 199916–20.…”

Empirical K-shell ionization cross-sections of elements from 4Be to 92U by proton impact

“…(The first table [10] contains contain 4300 data and the second table [13] contains 184 additional data.) In addition to these data, we extracted other data from experimental papers published from 1992 till 1999 [14][15][16][17][18]. So, we have at our disposal a database regrouping 5402 data points.…”