An account of recent work is given by the author and co-workers on the experimental determination of cross sections for excitation transfer between the (2)P((1/2)) and (2)P(3/2)resonance levels in potassium, rubidium and cesium, induced by inelastic collisions with alkali atoms and inert gas atoms in their ground states. Forty values of cross sections were obtained in a series of sensitized fluorescence experiments, in which alkali vapors and vapor-gas mixtures were irradiated with one component of the appropriate alkali resonance doublet, and the relative intensities of both components appearing in the fluorescent light were measured. The experiments indicate that the collisional interaction between an alkali atom in a (2)P state and a ground state inert gas atom probably occurs between the inert gas atom and the (2)P alkali valence electron which behaves like a quasi-free particle.

Collisional excitation transfer between the 2P1/2 and 2P3/2 levels in alkali atoms.

With the exception of the sulfur L‐absorption spectrum, measurements of all the soft x‐ray spectra from gaseous SF6 in their respective threshold regions are reported. The valence emission x‐ray spectra are interpreted in terms of a molecular orbital model of SF6 with the inclusion of sulfur d orbitals. The experimental emission profiles are in fair agreement with a calculated profile based on the assigned orbital ionization energies and molecular orbital theory. The sharp resonance structures in the absorption spectra are found to result from the potential barrier formed by the surrounding fluorine atoms and are consistent with the molecular orbital model. The identification of the absorption resonance structure in terms of transitions to ``virtual'' unoccupied electronic levels is substantiated by the observation of ``resonance radiation,'' i.e., x‐ray emission in coincidence with the peak positions in the absorption region. The sulfur Kα spectrum is also presented and discussed. A notable feature in th...

The Sulfur K and L and Fluorine K X‐Ray Emission and Absorption Spectra of Gaseous SF6

The total cross sections for inelastic collisions between sodium and inert gas atoms, leading to 3 2P1/2 ↔ 3 2P3/2 excitation transfer in sodium, have been determined in a series of sensitized fluorescence experiments with sodium – inert gas mixtures. The sodium vapor was maintained at a pressure of 5 × 10−7 mm Hg, at which there is no trapping of the resonance radiation, and the inert gas pressures ranged from 0 to 1 mm Hg. The cross sections Q1(3 2P1/2 → 3 2P3/2) and Q2(3 2P1/2 ← 3 2P3/2) are as follows: Na–He, 86.0 and 44.8 A2; Na–Ne, 67.0 and 35.4 A2; Na–Ar, 110 and 55.9 A2; Na–Kr, 85.0 and 43.6 A2; Na–Xe, 89.8 and 45.6 A2. The ratios Q1/Q2 are in agreement with the value predicted from the principle of detailed balancing and the cross sections also agree, as to order of magnitude, with some theoretically predicted values.

Sensitized fluorescence in vapors of alkali metals. IX. Energy transfer in collisions between sodium and inert gas atoms

Excitation of analytes and enhancement of emission intensities in a d.c. plasma jet: a critical review leading to proposed mechanistic models

2014 We have measured excitation transfer cross-sections in collisions of highly excited cesium atoms with cesium or noble gas atoms in their ground state. The comparaison of experimental results with theoretical values suggests that mechanisms which have been neglected for the lower levels, have to be taken into account in this case. A better knowledge of interatomic forces is expected from these studies. LE JOURNAL DE PHYSIQUE TOME 33, AVRIL 1972, Classification : Physics Abstracts 13.20

https://hal.archives-ouvertes.fr/jpa-00207255/document

Transfert d'excitation électronique, par collision atomique, entre niveaux élevés d'un atome de césium

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Fred L. Mohler

Papers

Resonance Radiation of Sodium Vapor Excited by one of the D Lines