Excitation of Ne, Ar, Kr and Xe by He+ impact (0.3–35 KeV; 3000Å–6000Å)

Abstract

Impact radiation resulting from collisions of He + with Ne, Ar, Kr and Xe for He + kinetic energies in the range 0.3–35 KeV is studied in the wavelength region between 3000 Å and 6000 Å. Particular attention is paid to the relatively strong production of ion lines of the target atom, whose emission cross sections in many cases show a remarkable increase with decrease in impact energy. These spectral lines are produced when the helium ion captures an electron from the target atom with a simultaneous excitation of the resultant ion. The unexpectedly high emission cross sections at low impact energies may be explained in terms of pseudocrossing of the two potential curves of the interacting atomic systems before and after the reaction. For comparison, some measurements have been taken with H + and H + 2, where the effect of pseudocrossing does not seem to be present. For He + incident on Ne, atomic lines are observed which also show an increase in intensity with decreasing impact energies. Similar lines for Ar, Kr and Xe could not be studied, because most of these lines are present above 6000 Å, outside the spectral range of the apparatus.