Atomic and Molecular Photoelectron Angular Distributions Measured near Threshold

Abstract

The differential angular distributions of photoelectrons emitted in the formation of various ionic states have been determined for Ar, Kr, Xe, H2, N2, and O2. Where possible several photon energies have been employed, the 21.21-eV He resonance line and the 16.67- and 16.85-eV Ne resonance doublet. In most cases the angular dependence for the photoelectron emission can be described by a function of the form 1 + βP2(cosΘ). For certain of the rare gases ionized by the Ne resonance doublet large deviations from this prediction were obtained. These deviations are related to the energy of the outgoing electron and the structure of the ionic species formed.

Experimental characterization of the Xe 5p photoionization by angle- and spin-resolved photoelectron spectroscopy

“…Excellent data exist for the asymmetry parameter fl, which has been measured at resonance wavelengths of discharge sources [25,[98][99][100][101][102][103][104][105][106][107] as well as with synchrotron radiation [87-89, 108, 109]. In addition to the spin-parameters A, e and ~ measured with circularly polarized synchrotron radiation, 4-values from experiments with unpolarized line radiation [23,26] were used (at the HeI (21.22eV) and NeIb (16.85 eV) resonance lines).…”

Photoelectron angular distributions from H2 and D2

“…All of the theoretical calculations predict a large asymmetry and a slow variation of a(H 2 ) with energy, but they differ in the precise [18][19][20][21][22][23][24] tend toward larger asymmetries than has been measured using synchrotron radiation. We note that the resonance line radiation is concentrated into a much smaller bandpass (~hv = 10 meV FWHM), than the synchrotron radiation (~hv = 109 meV FWHM).…”

“…Several theoretical calculations of a(H 2 ) have been published [4][5][6][7][8][9][10][11][12][13][14][15][16][17], and a number of groups have measured a(H 2 ) using discrete resonance line radiation [18][19][20][21][22][23][24]. Recently, Marr et al [25] reported measurements over the photon energy range 18-30 eV using synchrotron radiation.…”

Total Electron—Atom Collision Cross Sections at Low Energies—A Critical Review

“…This subject is also discussed at length by various authors (McGowan, 1967;Golden and Bandel, ' 1965) although there is by no means universal agreement over the best means of minimizing it. It is, however, generally recognized that polished metal surfaces are particularly efficient reflectors of electrons, and that some sort of coating )electron velvet (Marmet 'Unless otherwise stated in the original articles, it must be assumed that the apparatus contained the usual assortment of experimentalists materials, including brass, copper, nickel, etc.…”