Coherent Excitation of He Atoms by Proton Impact

Stephen J. Smith

O Schöller, J S Briggs, R. M. Dreizler

The density matrix describing excitation of the n=2 and n=3 levels of atomic hydrogen under proton impact is calculated, both in the first Born approximation and in a close-coupling expansion in target eigenstates. Various ways in which the properties of the excited state can be characterized in terms of certain linear combinations of density matrix elements are discussed. A new characterisation, based on an extrapolation below threshold of parameters describing the angular distribution of low-velocity ionised electrons, is suggested.

Christian Kurtsiefer, Christopher R. Ekstrom, D. Voigt +3 more

G. Gabrielse

A. G. Petrashen, N. V. Sytenko

It is shown that laser generation is possible in principle upon coherent excitation according to the V-scheme of the (1s2p)3 P j levels with j = 1, 2 of a helium atom from the (1s2s)3 S 1 level of the same atom when the latter level is, in turn, populated by electron or proton impact.

E.G. Aleksandrov