Collisional Depolarization of Mercury Resonance Radiation

1973 ◽  
Vol 51 (7) ◽  
pp. 724-726 ◽  
Author(s):  
R. A. Phaneuf ◽  
J. Pitre ◽  
K. Hammond ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Resonance Radiation

The depolarization of mercury resonance radiation (2537 Å), induced in collisions of Hg(63p1) atoms with various buffer gases, has been investigated using the method of delayed coincidences. The experiments yielded the following depolarization cross sections. Hg–He, 37.8 Å2; Hg–Ne, 43.5 Å2; Hg–Ar, 72.9 Å2; Hg–Kr, 101 Å2; Hg–Xe, 144 Å2; Hg–N2, 120 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.

THE QUENCHING OF POTASSIUM RESONANCE RADIATION BY HYDROGEN AND DEUTERIUM

1954 ◽  
Vol 32 (10) ◽  
pp. 961-968 ◽  
Author(s):  
W. M. Smith ◽  
J. A. Stewart ◽  
G. W. Taylor
Keyword(s):  
Cross Sections ◽  
Resonance Radiation ◽  
Temperature Range

The quenching of the resonance radiation of potassium by hydrogen and deuterium has been studied over the temperature range 71 °C to 83 °C. The quenching cross sections at 76 °C were found to be 1.56 × 10−16 cm2 and 1.10 × 10−16 cm2 respectively.

The determination of cross sections for the quenching of resonance radiation of metal atoms II. Results for potassium, rubidium and caesium

1968 ◽  
Vol 303 (1475) ◽  
pp. 453-465 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Cross Sections ◽  
Resonance Radiation ◽  
Fluorescence Technique ◽  
Metal Atoms

The flame fluorescence technique has been used to study the fluorescence of the metals potassium, rubidium and caesium. Measurements of the intensity of fluorescence of each of these metals in isothermal groups of hydrogen-oxygen flames diluted with each of the gases argon, helium, nitrogen and carbon dioxide have given the following values (Å 2 ) for the square of the distance between the centres of colliding species, σ 2 : for potassium: σ 2 H 2 = 1.03 ± 0.05 σ 2 H 2 O = 0.9 ± 0.3 σ 2 Ar < 0.2 σ 2 He < 0.08 σ 2 N 2 = 5.6 ± 0.3 σ 2 CO = 12.4 ± 0.8 σ 2 CO 2 = 21.4 ± 1.0 σ 2 O 2 = 15.5 ± 1.5 for rubidium: σ 2 H 2 = 0.61 ± 0.1 σ 2 H 2 O = 1.27 ± 0.15 σ 2 Ar < 0.3 σ 2 He < 0.11 σ 2 N 2 = 6.1 ± 0.6 σ 2 CO = 11.8 ± 2.0 σ 2 CO 2 = 24 ± 2 σ 2 O 2 = 25 ± 5 for caesium: σ 2 H 2 = 1.7 ± 0.3 σ 2 H 2 O = 5.5 ± 1.6 σ 2 Ar < 0.9 σ 2 He < 0.4 σ 2 N 2 = 25 ± 6

The determination of cross-sections for the quenching of resonance radiation of metal atoms. IV. Results for lithium

1968 ◽  
Vol 306 (1486) ◽  
pp. 413-421 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Cross Section ◽  
Cross Sections ◽  
Hollow Cathode ◽  
Alkali Metals ◽  
Resonance Radiation ◽  
The Other ◽  
Fluorescence Technique ◽  
Metal Atoms

The flame fluorescence technique has been used to study the fluorescence of lithium in sets of isothermal hydrogen-oxygen flames diluted with each of the gases argon, nitrogen and carbon dioxide. The measurements have given the following values (Å 2 ) for the quenching cross-sections, σ 2 , of lithium in the 2 p 2 P state: σ 2 H 2 = 5⋅2, σ 2 H 2 O ═ 1⋅9, σ 2 N 2 ═ 6⋅75, σ 2 CO ═ 12⋅6, σ 2 CO 2 ═ 9⋅2, σ 2 Ar ≼ 0⋅3. The cross-section is defined as the square of the distance between centres of colliding species. These values are compared with those previously reported (Jenkins 1966, 1968) for the other alkali metals and their interpretation discussed. Details of the high intensity hollow cathode lamp used as a source of lithium resonance radiation are also given.

The determination of cross sections for quenching of resonance radiation of metal atoms III. Results for thallium

1968 ◽  
Vol 303 (1475) ◽  
pp. 467-475 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Cross Section ◽  
Cross Sections ◽  
Rate Constants ◽  
Resonance Radiation ◽  
Metal Atoms ◽  
The Cross

The intensity of fluorescence of thallium has been measured in hydrogen-oxygen flames diluted with each of the gases, argon, helium, nitrogen and carbon dioxide and the measurements used to obtain the following values for the quenching cross section (Å 2 ) for the 7 s 2 S ½ state of thallium σ 2 H 2 = 0.03, σ 2 O 2 = 13.2 ± 1.5, σ 2 N 2 = 6.4 ± 0.2, σ 2 H 2 O = 1.75 ± 0.2, σ 2 CO = 13.6 ± 0.8, σ 2 CO 2 = 32.5 ± 1.5, σ 2 Ar ≤ 0.1, σ 2 He ≤ 0.12. These values for the cross sections have been used to re-calculate the rate constants of the reactions, Tl + H + X → H X + Tl*, where X = H, OH, Cl or Br, from the data obtained by Phillips & Sugden (1961). The re-calculated values are lower than the original ones by a factor of 2.2.

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.

The determination of cross sections for the quenching of resonance radiation of metal atoms I. Experimental method and results for sodium

1966 ◽  
Vol 293 (1435) ◽  
pp. 493-511 ◽  
Keyword(s):  
Experimental Method ◽  
Cross Sections ◽  
Resonance Radiation ◽  
Line Broadening ◽  
Compound Formation ◽  
Metal Atoms ◽  
Sodium Atoms ◽  
The Cross ◽  
Oxygen Flame

A method of determining the cross sections for the quenching of excited metal atoms by molecules and atoms which may be present in flames is described. The method has been applied to the quenching of sodium atoms in the 3 p 2 P state and the following results (in Å 2 ) for the square of the distance between the centres of colliding species, σ 2 , obtained: σ 2 H 2 = 2.87 ± 0.1; σ 2 N 2 = 6.95 ± 0.15; σ 2 CO = 11.9 ± 0.4; σ 2 CO 2 = 17.0 ± 0.4; σ 2 H 2 O = 0.5 ± 0.3; σ 2 O 2 = 12.3 ± 0.5; σ 2 Ar < 0.1; σ 2 He < 0.1. These cross sections have been measured at temperatures in the range 1400°K to about 1800°K and found to be independent of the temperature. The values for the cross sections are derived from measurements of the fluorescence of sodium in hydrogen-oxygen flame diluted with various other gases. This method is believed to be free of uncertainties due to self-absorption, compound formation, line broadening effects and uncertain velocity distributions. Where values for cross sections have been obtained by other workers they are compared with these results and possible reasons for the discrepancies are discussed.

Quenching and Depolarization of Mercury Resonance Radiation

1971 ◽  
Vol 49 (15) ◽  
pp. 1976-1981 ◽  
Author(s):  
J. S. Deech ◽  
J. Pitre ◽  
L. Krause
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Resonance Radiation

The quenching and depolarization of mercury resonance radiation (2537 Å), induced in collisions of Hg(63P1) atoms with various molecules has been investigated using the method of delayed coincidences. The following total quenching cross sections have been obtained for the process Hg(63P1) → Hg(63P0, 61S0): Hg–H2, 24.6 Å2; Hg–D2, 22.7 Å2; Hg–CO, 21.7 Å2; Hg–CO2, 10.2 Å2; Hg–O2, 60.5 Å2; Hg–14N2, 0.73 Å2; Hg–15N2, 0.78 Å2; and Hg–Xe, < 0.002 Å2. A cross section of 267 Å2 has been measured for the depolarization of the resonance radiation by collisions with CO2 molecules.

Sensitized fluorescence in vapors of alkali metals. XII. 42P1/2–42P3/2 mixing in potassium, induced in collisions with ground-state rubidium atoms

1969 ◽  
Vol 47 (2) ◽  
pp. 223-226 ◽  
Author(s):  
E. S. Hrycyshyn ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Ground State ◽  
Alkali Metals ◽  
Resonance Radiation ◽  
Total Cross Sections ◽  
Sensitized Fluorescence ◽  
Rubidium Atoms ◽  
Partial Pressures ◽  
Potassium Vapor ◽  
Detailed Balancing

The total cross sections for collisions between excited potassium and unexcited rubidium atoms, leading to the transfer of excitation between the 42P states in potassium, have been determined in a sensitized fluorescence experiment. The experiments were carried out at partial pressures of potassium vapor lower than 10−5 mm Hg, at which the imprisonment of resonance radiation may be disregarded. The cross sections Q12″ (42P1/2 → 42P3/2) and Q21″ (42P1/2 ← 42P3/2) equal 260 Å2 and 175 Å2, respectively, and are in the ratio predicted by the principle of detailed balancing.

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