Accession Number : ADA020134

Title :   Low Energy Inelastic Atomic and Molecular Collisions.

Descriptive Note : Final rept. 31 Jul 72-30 Sep 75,


Personal Author(s) : Pollack,Edward ; Smith,Winthrop W.

Report Date : 17 DEC 1975

Pagination or Media Count : 11

Abstract : Differential scattering in the Ar(+)+N2 and He(+)+H2 systems was studied in detail at low keV energies and small scattering angle. Charge exchange processes were found to be important in these systems. It was demonstrated that the collision involves the entire molecule and that vibro-rotational and electronic excitation occur independently. Only selected electronic states of the molecules participate in the scattering. Ionization in Ar+Ar collisions was studied and was attributed to both single electron excitation processes and to the excitation of autoionizing states. Studies of low energy He(+)+He collisions have shown strong energy dependent oscillations in the polarization of light emitted from the 3d states of He. Coincidence measurements on electrons ejected from 25 keV Ar(+)+Ar collisions show the presence of fast and slow electrons. The slow electrons may be ejected after as well as before the fast Auger electrons. Coincidence measurements on the L2,3 M x-ray yield were made at energies from 16-30 keV in Ar(+)+Ar. Enhancement of the fluorescence yield above 20 keV is attributed to M shell excitation. Vacuum ultraviolet spectra in the range of 500-1100A were observed in 10-30 keV rare gas ion-atom collisions. The results suggest correlations between inner and outer shell excitations.

Descriptors :   *Inelastic scattering, Helium, X ray spectra, Low energy, Auger electrons, Excitation, Atomic energy levels, Particle collisions, Gas ionization, Auger electron spectroscopy, Emission spectra, Molecular vibration, Molecular rotation, Argon, Neon, Nitrogen

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE