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.

Sensitized fluorescence in thallium induced in collisions with Hg(63P1) atoms

1978 ◽  
Vol 56 (7) ◽  
pp. 891-896 ◽  
Author(s):  
M. K. Wade ◽  
M. Czajkowski ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Ground State ◽  
Excitation Transfer ◽  
Resonance Radiation ◽  
Resonance Fluorescence ◽  
Collisional Excitation ◽  
Vapor Mixture ◽  
Sensitized Fluorescence ◽  
Intensity Measurements ◽  
Metallic Vapor

The transfer of excitation from excited mercury atoms to ground-state thallium atoms was investigated using techniques of sensitized fluorescence. A Hg–Tl vapor mixture contained in a quartz cell was irradiated with Hg 2537 Å resonance radiation which caused the mercury atoms to become excited to the 63P1, state. Subsequent collisions between the Hg(63P1) and Tl(62P1/2) atoms resulted in the population of the 82S1/2, 62D, and 72S1/2 thallium states, whose decay gave rise to sensitized fluorescence of wavelengths 3231, 3520, 3776, and 5352 Å. Intensity measurements on the sensitized fluorescence and on the Hg 2537 Å resonance fluorescence, observed at right angles to the direction of excitation, yielded cross sections of 3.0, 0.3, and 0.05 Å2 for collisional excitation transfer from Hg(63P1) to the 82S1/2, 62D, and 72S1/2 states in thallium, respectively. The results are fully consistent with previously determined cross sections for excitation transfer in other binary metallic vapor systems.

Disorientation of Cs(62P1/2) atoms, induced in collisions with noble gases

1976 ◽  
Vol 54 (7) ◽  
pp. 748-752 ◽  
Author(s):  
B. Niewitecka ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Noble Gas ◽  
Zero Magnetic Field ◽  
Zero Field ◽  
Buffer Gas ◽  
Resonance Fluorescence ◽  
Circularly Polarized ◽  
Low Field ◽  
Good Agreement ◽  
Gas Pressures

The disorientation of 62P1/2 cesium atoms, induced in collisions with noble gas atoms in their ground states, was systematically investigated by monitoring the depolarization of cesium resonance fluorescence in relation to noble gas pressures. The Cs atoms, contained together with a buffer gas in a fluorescence cell and located in zero magnetic field, were excited and oriented by irradiation with circularly polarized 8943 Å resonance radiation, and the resonance fluorescence, emitted in an approximately backward direction, was analyzed with respect to circular polarization. The experiments yielded the following disorientation cross sections which have been corrected for the effects of nuclear spin: Cs–He: 4.9 ± 0.7 Å2; Cs–Ne: 2.1 ± 0.3 Å2; Cs–Ar: 5.6 ± 0.8 Å2; Cs–Kr: 5.8 ± 0.9 Å2; Cs–Xe: 6.3 ± 0.9 Å2. The results are in good agreement with most of the available zero-field and low-field data.

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.

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.

Coherence Transfer between the 2P1/2 and 2P3/2 States in Potassium, Induced in Collisions with Noble Gas Atoms and with Molecules

1973 ◽  
Vol 51 (4) ◽  
pp. 425-430 ◽  
Author(s):  
B. Niewitecka ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Noble Gas ◽  
Coherence Transfer ◽  
Circularly Polarized ◽  
Sensitized Fluorescence ◽  
Potassium Vapor ◽  
Simple Molecules

The transfer of coherence accompanying 42P1/2 → 42P3/2 transfer of excitation induced in collisions between 42P1/2 potassium atoms and noble gas atoms as well as some simple molecules, was studied in a series of sensitized fluorescence experiments. Mixtures of potassium vapor at 6 × 10−7 Torr with the various buffer gases were irradiated with circularly polarized D1(σ+) light and the relative intensities of the σ+ and σ− fractions of both the D1 and D2 fluorescent components were determined in relation to the pressures of the buffer gases. The experiments yielded the following cross sections for coherence transfer: K–He:1.7 Å2; K–Ne :0.8 Å2; K–Ar < 0.5 Å2; K–H2 :3.5 Å2; K–CH4 :7.0 Å2; K–CD4:7.7 Å2.

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.

Disorientation of Na(32P1/2) Atoms, Induced in Collisions with Noble Gases

1974 ◽  
Vol 52 (20) ◽  
pp. 1956-1960 ◽  
Author(s):  
B. Niewitecka ◽  
T. Skaliński ◽  
L. Krause
Keyword(s):  
Circular Polarization ◽  
Cross Sections ◽  
Nuclear Spin ◽  
Noble Gas ◽  
Gas Pressure ◽  
Degree Of Polarization ◽  
Low Density ◽  
Resonance Fluorescence ◽  
Sodium Vapor ◽  
Circularly Polarized

The cross sections for disorientation of 32P1/2 sodium atoms, induced in collisions with noble gas atoms, have been determined by following the depolarization of Na–D1 resonance fluorescence in relation to noble gas pressure. Sodium vapor at low density, mixed with a noble gas in a fluorescence cell, was irradiated with circularly polarized D1 resonance radiation and the resulting D1 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 effects due to nuclear spin. Na–He: 28.1 ± 4.0 Å2; Na–Ne: 27.8 ± 4.0 Å2; Na–Ar: 57.0 ± 8.0 Å2; Na–Kr: 78.0 ± 10 Å2; Na–Xe: 87.0 ± 13 Å2.

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.

Sensitized Fluorescence in Sodium Induced in Collisions with Hg(63P1) Atoms

1973 ◽  
Vol 51 (3) ◽  
pp. 334-342 ◽  
Author(s):  
M. Czajkowski ◽  
G. Skardis ◽  
L. Krause
Keyword(s):  
Excitation Energy ◽  
Cross Sections ◽  
Ground State ◽  
Absolute Intensity ◽  
Resonance Radiation ◽  
Inelastic Collisions ◽  
Sensitized Fluorescence ◽  
Subsequent Decay ◽  
Intensity Measurements ◽  
Fluorescent Spectrum

Collisional transfer of excitation from mercury to sodium was investigated using methods of sensitized fluorescence. A mixture of mercury and sodium vapors at low pressure was irradiated with Hg 2537 Å resonance radiation, producing a population of Hg(63P1) atoms whose inelastic collisions with ground-state sodium atoms resulted in a transfer of excitation energy to close-lying S, P, and D states in sodium. The subsequent decay of these states manifested itself in the emission of a sensitized fluorescent spectrum. Absolute intensity measurements on the components of the spectrum yielded 21 cross sections whose magnitudes range from 0.02 to 38.5 Å2 and which exhibit a pronounced resonance with ΔE, the energy defect between Hg (63P1) and the appropriate level in sodium.

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