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.

Sensitized Fluorescence in Vapors of Alkali Atoms. XIII. 62P1/2−62P3/2 Excitation Transfer in Rubidium, Induced in Collisions with Noble Gas Atoms

1972 ◽  
Vol 50 (16) ◽  
pp. 1826-1832 ◽  
Author(s):  
I. Siara ◽  
E. S. Hrycyshyn ◽  
L. Krause
Keyword(s):  
Fine Structure ◽  
Cross Sections ◽  
Noble Gas ◽  
Excitation Transfer ◽  
Fluorescent Intensity ◽  
Rubidium Vapor ◽  
Sensitized Fluorescence ◽  
Fine Structure Splitting ◽  
Alkali Atoms ◽  
Structure Splitting

The cross sections for excitation transfer between the 62P fine-structure substates in rubidium, induced in collisions with noble gas atoms, have been determined in a series of sensitized fluorescence experiments. Mixtures of rubidium vapor and noble gases at pressures varying in the range 0–5 Torr were irradiated with each component of the second 2P rubidium doublet in turn and the following cross sections for 2P mixing were obtained from measurements of sensitised-to-resonance fluorescent intensity ratios. Rb–He: Q12(2P1/2 → 2P3/2) = 29.3 Å2; Q21(2P1/2 ← 2P3/2) = 19.0 Å2. Rb–Ne: Q12 = 10.3 Å2; Q21 = 6.4 Å2. Rb–Ar: Q12 = 24.0 Å2; Q21 = 14.9 Å2. Rb–Kr: Q12 = 23.2 Å2; Q21 = 14.6 Å2. Rb–Xe: Q12 = 43.9 Å2; Q21 = 27.7 Å2 In their dependence on the magnitude of the fine-structure splitting, the values are consistent with previously determined cross sections for mixing in the first and third 2P doublets of alkali atoms.

52P1/2 ↔ 52P3/2 excitation transfer in rubidium induced in collisions with CH4, CH2D2, and CD4 molecules

1980 ◽  
Vol 58 (7) ◽  
pp. 1047-1048 ◽  
Author(s):  
R. A. Phaneuf ◽  
L. Krause
Keyword(s):  
Energy Transfer ◽  
Temperature Dependence ◽  
Isotope Effect ◽  
Cross Sections ◽  
Noble Gas ◽  
Rotational Energy ◽  
Excitation Transfer ◽  
Sensitized Fluorescence ◽  
Temperature Range ◽  
Rotational Energy Transfer

The temperature dependence of cross sections for 52P1/2 ↔ 52P3/2 excitation transfer in rubidium, induced in collisions with CH4, CH2D2, and CD4 molecules, has been investigated using methods of sensitized fluorescence over a temperature range 300–650 K. The cross sections, which are of the order of 30 Å2 and which exceed similar cross sections for collisions with noble gas atoms by at least two orders of magnitude, exhibit an isotope effect which is ascribed to the phenomenon of electronic-to-rotational energy transfer.

Temperature dependence of cross sections for 72P1/2 ↔ 72P3/2 excitation transfer and for quenching in cesium, induced in collisions with H2, N2, CH4, and CD4

1982 ◽  
Vol 60 (2) ◽  
pp. 239-244 ◽  
Author(s):  
I. N. Siara ◽  
R. U. Dubois ◽  
L. Krause
Keyword(s):  
Energy Transfer ◽  
Temperature Dependence ◽  
Cross Sections ◽  
Rotational Energy ◽  
Excitation Transfer ◽  
Sensitized Fluorescence ◽  
Temperature Range ◽  
Rotational Energy Transfer ◽  
Order Of Magnitude

The temperature dependence of cross sections for 72P1/2 ↔ 72P3/2 excitation transfer in cesium, as well as the effective quenching of these states, induced in collisions with H2, N2, CH4, and CD4 molecules have been investigated in a series of sensitized fluorescence experiments over a temperature range 390–640 K. The 72P mixing cross sections are of the order of 10−15 cm2 and exceed by at least one order of magnitude similar cross sections for mixing by collisions with Ne, Ar, Kr, and Xe. The large sizes of the mixing cross sections and their variation with temperature are ascribed to a phenomenon of electronic-to-rotational energy transfer.

Inelastic collisions between excited alkali atoms and molecules. V. Sensitized fluorescence in mixtures of sodium with N2, H2, HD, and D2

1968 ◽  
Vol 46 (19) ◽  
pp. 2127-2131 ◽  
Author(s):  
M. Stupavsky ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Ground State ◽  
Resonance Effect ◽  
Excitation Transfer ◽  
Inelastic Collisions ◽  
Sodium Vapor ◽  
Sensitized Fluorescence ◽  
Atoms And Molecules ◽  
Alkali Atoms ◽  
Exciting Beam

3 2P1/2 ↔ 3 2P3/2 excitation transfer in sodium, induced in inelastic collisions with ground-state N2, H2, HD, and D2 molecules, has been investigated in a series of sensitized fluorescence experiments. Mixtures of sodium vapor at a pressure of 5 × 10−7 Torr, and the gases, were irradiated with each NaD component in turn, and the fluorescence which contained both D components was monitored at right angles to the direction of the exciting beam. Measurements of the relative intensities of the NaD fluorescent components yielded the following collision cross sections for excitation transfer. For Na–N2 collisions: Q12(2P1/2 → P3/2) = 144 Å2, Q21(2P1,2 ← 2P3/2) = 76 Å2 for Na–H2 collisions: Q12 = 80 Å2, Q21 = 42 Å2. For Na–HD collisions: Q12 = 84 Å2, Q21 = 44 Å2. For Na–D2 collisions: Q12 = 98 Å2, Q21 = 52 Å2. The cross sections Q21 exhibit a slight resonance effect between the atomic and molecular rotational transitions.

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. VII. Sensitized fluorescence and quenching in mixtures of rubidium with H2, HD, D2, N2, CH4, CD4, C2H4, and C2.H6

1970 ◽  
Vol 48 (22) ◽  
pp. 2761-2768 ◽  
Author(s):  
E. S. Hrycyshyn ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Photon Counting ◽  
Inelastic Collisions ◽  
Exciting Light ◽  
Rubidium Vapor ◽  
Sensitized Fluorescence ◽  
Alkali Atoms ◽  
Order Of Magnitude ◽  
Resonance Doublet ◽  
Intensity Ratios

52P1/2 ↔ 52P3/2 mixing and 52S1/2 ← 52P1/2, 2P3/2 quenching in rubidium, induced in collisions with ground state H2, HD, D2, N2, CH4, CD4, C2H4, and C2H6 molecules, have been investigated using methods of sensitized fluorescence. The rubidium vapor mixed with each of the gases was excited in turn by each component of the rubidium resonance doublet, and the resulting fluorescence, emitted at right angles to the direction of the exciting light, was resolved into the two fine-structure components whose intensity ratios were measured in relation to the gas pressure using photon counting techniques. The measurements yielded the following cross sections for the mixing and quenching collisions.For H2: Q12(2P1/2 → 2P3/2) = 11 Å2, Q21(2P1/2 ← 2P3/2) = 15 Å2, Q10(2S1/2 ← 2P1/2) = 6 Å2, Q20(2S1/2 ← 2P3/2) = 3 Å2.[Formula: see text]The mixing cross sections agree with theoretical values within an order of magnitude.

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.

Inelastic collisions between excited alkali atoms and molecules. IV. Sensitized fluorescence and quenching in mixtures of cesium with N2, H2, HD, and D2

1968 ◽  
Vol 46 (9) ◽  
pp. 1051-1057 ◽  
Author(s):  
D. A. McGillis ◽  
L. Krause
Keyword(s):  
Vapor Pressure ◽  
Multiple Scattering ◽  
Cross Sections ◽  
Ground State ◽  
Inelastic Collisions ◽  
Cesium Vapor ◽  
Sensitized Fluorescence ◽  
Alkali Atoms ◽  
Exciting Beam ◽  
Resonance Doublet

6 2P1/2 ↔ 6 2P3/2 mixing and 6 2S1/2 ← 6 2P1/2,3/2 quenching in cesium, induced in collisions with ground state N2, H2, HD, and D2 molecules, have been investigated using techniques of sensitized fluorescence. Mixtures of cesium vapor and the gases, in which the cesium vapor pressure was kept very low to avoid multiple scattering, were irradiated with each component of the cesium resonance doublet in turn. The fluorescence which contained both components of the doublet was observed in a direction perpendicular to that of the exciting beam. Measurements of the relative intensities of the fluorescent components yielded the following cross sections for mixing and quenching. For Cs–N2 collisions: Q12(2P1/2 → 2P3/2) = 4.7 Å2, Q21(2P1/2 ← 2P3/2) = 25 Å2, Q10(2S1/2 ← 2P1/2) = 77 Å2, Q20(2S1/2 ← 2P3/2) = 69 Å2. For Cs–H2 collisions: Q12 = 6.7 Å2, Q21 = 44 Å2, Q10 = 7 Å2, Q20 = 5 Å2. For Cs–HD collisions: Q12 = 4.8 Å2, Q21 = 32 Å2, Q10 = 4 Å2, Q20 = 3 Å2. For Cs–D2 collisions: Q12 = 4.2 Å2, Q21 = 28 Å2, Q10 = 8 Å2, Q20 = 7 Å2. The Cs–N2 and Cs–H2 cross sections supersede the values published previously (McGillis and Krause 1967). The cross sections Q21 appear to exhibit resonances with molecular rotational transitions.

Coherence Transfer Between the 32P1/2 and 32P3/2 States in Sodium, Induced in Collisions with Noble Gas Atoms

1973 ◽  
Vol 51 (9) ◽  
pp. 993-997 ◽  
Author(s):  
B. Niewitecka ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Noble Gas ◽  
Excitation Transfer ◽  
Resonance Radiation ◽  
Buffer Gas ◽  
Resonance Fluorescence ◽  
Sodium Vapor ◽  
Coherence Transfer ◽  
Sensitized Fluorescence ◽  
Simultaneous Transfer

Coherence transfer accompanying 32P1/2 → 32P3/2 excitation transfer in sodium, induced in collisions with noble gas atoms, has been investigated using methods of sensitized fluorescence. Oriented 32P1/2 sodium atoms were produced by irradiating a mixture of sodium vapor and a noble gas with D1σ+ resonance radiation, and their subsequent collisions with the buffer gas atoms resulted in the simultaneous transfer of coherence and excitation from the 2P1/2 state to the 2P3/2 state. Measurements of the ratio of circular polarizations of the D2 sensitized fluorescence and D1 resonance fluorescence resulted in the following cross sections for coherence transfer. Na–He : 7.1 ± 0.7 Å2; Na–Ne : 6.2 ± 0.6 Å2; Na–Ar : 12.0 ± 1.2 Å2; Na–Kr : 6.8 ± 0.7 Å2; Na–Xe : 6.9 ± 0.7 Å2.

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.

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