Cross Sections for Depolarization of 62P3/2 Cesium Atoms Induced in Collision with Noble Gases from D2 Optical Pumping

1980 ◽  
Vol 35 (11) ◽  
pp. 1245-1248
Author(s):  
P. Rudedcki
Keyword(s):  
Energy Transfer ◽  
Cross Sections ◽  
Optical Pumping ◽  
Noble Gases ◽  
Circularly Polarized ◽  
Alkali Atoms ◽  
The Cross ◽  
Cesium Atoms

Abstract Possibilities of examing the relaxation of alkali atoms in 62P3/2 state by analysing the pumping process with a weak circularly polarized D2 line are presented. Results of an experiment on Cs-He and Cs-Ne systems have also been given. Assuming the J-randomization model for relaxation of alkali atoms in 2P3/2 state and neglecting energy transfer between 62PJ states, we obtained the cross sections for relaxation: Cs-He, 62.6 ± 10.0; Cs-Ne, 54.0 ± 9.0; in 10-16 cm2 units.

Inelastic Collisions Between Excited Alkali Atoms and Molecules X. Temperature Dependence of Cross Sections for 2P1/2↔2P3/2 Mixing in Cesium, Induced in Collisions with Deuterated Hydrogens, Ethanes, and Propanes

1974 ◽  
Vol 52 (7) ◽  
pp. 589-591 ◽  
Author(s):  
E. Walentynowicz ◽  
R. A. Phaneuf ◽  
L. Krause
Keyword(s):  
Energy Transfer ◽  
Temperature Dependence ◽  
Isotope Effect ◽  
Cross Sections ◽  
Rotational Energy ◽  
Inelastic Collisions ◽  
Atoms And Molecules ◽  
Rotational Energy Transfer ◽  
Alkali Atoms ◽  
The Cross

The dependence on temperature of the cross sections for 2P1/2 ↔ 2P3/2 mixing in cesium, induced in collisions with various deuterated hydrogen, ethane and propane molecules, has been studied in the range 290–650 K. In the cases of hydrogen and ethane, the behavior of the cross sections was found to depend on the degree of deuteration of the molecules. The very large sizes of the mixing cross sections and the isotope effect observed in their variation with temperature, are ascribed to the phenomenon of electronic to rotational energy transfer.

Inelastic Collisions Between Excited Alkali Atoms and Molecules IX. An Isotope Effect in the Cross Sections for 62P1/2↔62P3/2 Mixing in Cesium, Induced in Collisions with Deuterated Methanes

1974 ◽  
Vol 52 (7) ◽  
pp. 584-588 ◽  
Author(s):  
E. Walentynowicz ◽  
R. A. Phaneuf ◽  
W. E. Baylis ◽  
L. Krause
Keyword(s):  
Energy Transfer ◽  
Isotope Effect ◽  
Cross Sections ◽  
Noble Gas ◽  
Inelastic Collisions ◽  
Semiclassical Theory ◽  
Vibrational States ◽  
Rotational Energy Transfer ◽  
Alkali Atoms ◽  
The Cross

The temperature dependence of cross sections for 62P1/2 ↔ 62P3/2 mixing in cesium, induced in collisions with CH4, CH3D, CH2D2, CHD3, and CD4 molecules, has been investigated in a series of sensitized fluorescence experiments over a temperature range 290–650 K. The various cross sections which are of the order of 10−15 cm2, and which exceed similar cross sections for cesium–noble gas collisions by 4 – 6 orders of magnitude, exhibit differences in their variation with temperature. This isotope effect in the collision cross sections is interpreted on the basis of a novel semiclassical theory of electronic to rotational energy transfer. The cross section for mixing induced by collisions with CF4, which was determined in a subsidiary experiment, and which is 2–3 times larger than the methane cross sections, does not show comparable behavior with temperature, probably because the energy transfer takes place to closely lying molecular vibrational states.

Transfer of Electronic Excitation between the 72P1/2 and 72P3/2 States of Cesium Induced by Collisions with Cesium Atoms

1974 ◽  
Vol 52 (17) ◽  
pp. 1641-1647 ◽  
Author(s):  
Paul W. Pace ◽  
J. B. Atkinson
Keyword(s):  
Cross Sections ◽  
Electronic Excitation ◽  
Empirical Relationship ◽  
Nitrogen Laser ◽  
Mixing Process ◽  
Transfer Processes ◽  
Radiation Trapping ◽  
Structure Splitting ◽  
The Cross ◽  
Cesium Atoms

The method of sensitized fluorescence has been employed to investigate the [Formula: see text] excitation transfer processes in cesium induced in collisions with ground state cesium atoms. The cesium vapor density was kept sufficiently low to enable the cross sections for the mixing process to be determined under single collision conditions and to ensure that radiation trapping and quenching were negligible. A nitrogen laser pumped dye laser was used to excite the cesium atoms to each of the 72P levels in turn and measurements of the relative intensities of fluorescence yielded the following cross sections: [Formula: see text] These results are consistent with the empirical relationship between the magnitude of the cross sections and the fine structure splitting that has previously been determined for the alkalis.

scholarly journals Energie- und Polarisationsübertragung zwischen Thallium D-Niveaus durch Stöße mit Edelgasatomen / Energy and polarisation transfer between Thallium D-levels induced by collisions with inert gas atoms

1973 ◽  
Vol 28 (2) ◽  
pp. 257-259
Author(s):  
B. Gelbhaar
Keyword(s):  
Energy Transfer ◽  
Cross Sections ◽  
Polarized Light ◽  
Inert Gas ◽  
The Cross

The cross sections for energy transfer from the 62D3/2 to the 62D5/2 Tl-level indcuced by collisions with inert gas atoms have been determined. The results in units of 10-16 cm2 are: Tl-He 35,1; Tl-Ne 3,7; Tl-Ar 2,3; Tl-Kr 7,5; Tl-Xe 10,8. In two modified experiments the transfer of orientation to the 62D5/2 level could be detected by exciting the 62D3/2 level with circulary polarized light.

Calculation of cross sections for the depolarization of 2P states in alkali atoms

1969 ◽  
Vol 47 (17) ◽  
pp. 1819-1827 ◽  
Author(s):  
E. P. Gordeyev ◽  
E. E. Nikitin ◽  
M. Ya. Ovchinnikova
Keyword(s):  
Electric Field ◽  
Cross Section ◽  
Cross Sections ◽  
Optical Pumping ◽  
Ground States ◽  
Inert Gas ◽  
Small Cross Section ◽  
Alkali Atoms ◽  
Helium Neon

Optical pumping experiments have yielded very large disorientation cross sections (40–100 Å2) for collisions between oriented 2P1/2 atoms of potassium, rubidium, cesium and thalium, and helium, neon, argon, krypton, and xenon atoms in their ground states, in contrast to the extraordinarily small cross section (< 10−5 Å2) for the depolarization of 2S1/2 atoms, as found by Gallagher and by Anderson and Ramsey. Franz, Leutert, and Shuey pointed out that, within the adiabatic model, the transition ψ(j = 1/2, m = 1/2) → ψ(j = 1/2, m = −1/2) is strongly forbidden in conformity with Kramer's theorem according to which it is impossible to split the two components ψ(j = 1/2, m = ± 1/2) in an electric field. In the present investigation it has been shown that the inclusion of an angular nonadiabatic operator (i.e. the operator responsible for Coriolis mixing of adiabatic electronic molecular states) makes possible such transitions. Calculations are presented of cross sections for the resulting depolarization induced in collisions between potassium, rubidium, and cesium, and inert gas atoms.

Sensitized Fluorescence in Vapors of Alkali Atoms XIV. Temperature Dependence of Cross Sections for 72P1/2–72P3/2 Mixing in Cesium, Induced in Collisions with Noble Gas Atoms

1974 ◽  
Vol 52 (11) ◽  
pp. 945-949 ◽  
Author(s):  
I. N. Siara ◽  
H. S. Kwong ◽  
L. Krause
Keyword(s):  
Temperature Dependence ◽  
Cross Sections ◽  
Noble Gas ◽  
Excitation Transfer ◽  
Sensitized Fluorescence ◽  
Alkali Atoms ◽  
Resonance Doublet ◽  
The Cross ◽  
Adiabatic Case

The cross sections for 72P1/2–72P3/2 excitation transfer in cesium, induced in collisions with noble gas atoms, have been determined in a series of sensitized fluorescence experiments at temperatures ranging from 405 to 630 K. The cross sections which lie in the range 0.06–20 Å2, exhibit a temperature dependence which, however, is less pronounced than in the more adiabatic case of the cesium resonance doublet.

Inelastic collisions between excited alkali atoms and molecules. VI. Sensitized fluorescence in mixtures of sodium with CH4, CD4, C2H2, C2H4, and C2H6

1969 ◽  
Vol 47 (12) ◽  
pp. 1249-1252 ◽  
Author(s):  
M. Stupavsky ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Inelastic Collisions ◽  
Fluorescent Light ◽  
Molecular Gas ◽  
Sodium Vapor ◽  
Total Cross Sections ◽  
Sensitized Fluorescence ◽  
Alkali Atoms ◽  
The Cross ◽  
Good Agreement

The total cross sections for 32P1/2–32P3/2 mixing in sodium, induced in collisions with CH4, CD4, C2H2, C2H4, and C2H6 molecules, have been determined using the method of sensitized fluorescence. The sodium vapor – molecular gas mixtures were irradiated with each NaD component in turn, and the cross sections were obtained from measurements of relative intensities of the two D components present in the fluorescent light. The cross sections are as follows. For CH4: Q12(2P1/2 → 2P3/2) = 148 Å2, Q21(2P1/2 ← 2P3/2) = 77 Å2; for CD4: Q12 = 151 Å2, Q21 = 81 Å2; for C2H2: Q12 = 182 Å2, Q21 = 96 Å2; for C2H4: Q12 = 178 Å2, Q21 = 94 Å2; for C2H6: Q12 = 182 Å2, Q21 = 95 Å2. The cross sections Q21 are in good agreement with the values calculated according to the theory of Callaway and Bauer.

Disorientation of K(42P1/2) Atoms, Induced in Collisions with Noble Gases

1975 ◽  
Vol 53 (15) ◽  
pp. 1499-1503 ◽  
Author(s):  
B. Niewitecka ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Noble Gas ◽  
Zero Magnetic Field ◽  
Degree Of Polarization ◽  
Low Density ◽  
Resonance Fluorescence ◽  
Circularly Polarized ◽  
Potassium Vapor ◽  
The Cross ◽  
Gas Pressures

The cross sections for disorientation of 42P1/2 potassium atoms, induced in collisions with noble gas atoms, have been determined in zero magnetic field by studying the depolarization of K(7699 Å) resonance fluorescence in relation to noble gas pressures. Potassium vapor at low density, mixed with a noble gas in a fluorescence vessel, was irradiated with circularly polarized 7699 Å potassium resonance radiation and the resulting resonance fluorescence, observed in an approximately backward direction, was analyzed with respect to circular polarization. The variation of the degree of polarization with gas pressure was interpreted on the basis of a 'J randomization' model for the collisions and yielded the following disorientation cross sections which are appropriately corrected for the effect of nuclear spin: K–He, 24 ± 4 Å2; K–Ne, 21 ± 3 Å2; K–Ar, 37 ± 5 Å2; K–Kr, 51 ± 7 Å2; K–Xe, 69 ± 9 Å2. The cross sections are significantly smaller than values obtained previously in kilogauss fields.

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