Disorientation of 42P1/2 potassium atoms, induced in resonant collisions

1979 ◽  
Vol 57 (12) ◽  
pp. 2222-2226 ◽  
Author(s):  
P. Skalinski ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Variable Magnetic Field ◽  
Fluorescent Light ◽  
Exciting Light ◽  
Constant Field ◽  
Resonance Fluorescence ◽  
Resonance Transition ◽  
Vapor Density ◽  
Scanning Method ◽  
Potassium Vapor

A (modified) Zeeman scanning method was used to determine the cross sections for disorientation of potassium atoms in the 42P1/2 resonance substate, induced in collisions with the ground-state atoms. Potassium vapor at densities of the order of 1011 cm−3 placed in a variable magnetic field was irradiated with σ+ polarized resonance radiation of wavelength 7699 Å emitted from a discharge lamp located in a constant field of 5.4 kG. The σ+ and σ− components of the resonance fluorescence emitted at right angles to the direction of excitation were monitored in relation to the vapor density as the variable field was scanned to make the σ+ resonance transition in the absorbing vapor coincide with the σ+ component present in the exciting light. As the vapor density increased, so did the admixture of the σ− component in the fluorescent light, which arises from collisional mixing between the mJ = 1/2 and mJ = −1/2 Zeeman substates. The resulting depolarization curve yielded the disorientation cross section σ1 = 4.0 × 10−11 cm2.

Disorientation and disalignment of 42P3/2 potassium atoms, induced in resonant collisions

1980 ◽  
Vol 58 (10) ◽  
pp. 1500-1506 ◽  
Author(s):  
P. Skalinski ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Selective Excitation ◽  
Variable Magnetic Field ◽  
Constant Field ◽  
Resonance Fluorescence ◽  
Vapor Density ◽  
Scanning Method ◽  
Total Cross Sections ◽  
Circularly Polarized ◽  
Potassium Vapor

The total cross sections for disorientation (σ1) and disalignment (σ2) of 42P3/2 potassium atoms, induced in collisions with the ground-state atoms, have been determined using a modified Zeeman scanning method. Potassium vapor at densities of the order of 1011 cm−3, contained in a fluorescence cell located in a kilogauss variable magnetic field, was irradiated with circularly polarized 7665 Å resonance radiation emitted from a discharge lamp located in a constant field of 5.4 kG. Scans of the variable field permitted selective excitation of single Zeeman components in the absorbing vapor. The σ+ and σ− components of the resulting resonance fluorescence emitted parallel to the scanning field were monitored in relation to the vapor density, as were the π and σ components emitted in the perpendicular direction. As the vapor density increased so did the frequency of the collisions which caused transfers among the Zeeman states in the vapor and thus disorientation and disalignment. The observed dependence of circular and linear depolarization of the fluorescence on the potassium density yielded the cross sections σ1 = 17 × 10−12 cm2 and σ2 = 21 × 10−2 cm2, corrected for imprisonment of radiation.

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.

SENSITIZED FLUORESCENCE IN VAPORS OF ALKALI METALS: I. ENERGY TRANSFER IN POTASSIUM–POTASSIUM COLLISIONS

1964 ◽  
Vol 42 (3) ◽  
pp. 535-547 ◽  
Author(s):  
G. D. Chapman ◽  
L. Krause ◽  
I. H. Brockman
Keyword(s):  
Energy Transfer ◽  
Cross Sections ◽  
Alkali Metals ◽  
Experimental Results ◽  
Fluorescent Light ◽  
Vapor Pressures ◽  
Selection Rules ◽  
Sensitized Fluorescence ◽  
Photoelectric Recording ◽  
Potassium Vapor

Sensitized fluorescence in potassium vapor at pressures between 10−5 mm Hg and 10−1 mm Hg was investigated to determine the cross sections for collisions of the second kind between unexcited and excited potassium atoms. An idealized fluorescence tube was used in the experiment and the fluorescent light was analyzed with a photoelectric recording spectrometer. The collision cross sections at low vapor pressures, where imprisonment of radiation is absent, are identical for both the 42P1/2 → 42P3/2 and 42P1/2 ← 42P3/2 transitions and equal 6.6 × 10−12 cm2 at 2 × 10−4 mm Hg. The experimental results are interpreted on the basis of new selection rules for sensitized fluorescence.

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.

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.

scholarly journals Defining the Cubature Changes of Historic St. Kinga Chamber in Bochnia Salt Mine, Using Laser Scanning Technology

2018 ◽  
Vol 35 ◽  
pp. 04006
Author(s):  
Anna Szafarczyk ◽  
Rafał Gawałkiewicz
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Linear Convergence ◽  
Three Dimension ◽  
Salt Mine ◽  
Unesco World Heritage ◽  
Scanning Method ◽  
World Heritage List ◽  
Discrete Information ◽  
Structural Deformations

In Poland, there are many mining enterprises, of historic character registered in the UNESCO World Heritage List. One of the oldest mining enterprises in Poland is the Salt Mine in Bochnia. The processes inside the rock mass require that surveying services carry out regular geometric control of the cavities. A particular attention should be paid (due to its sacral function) on St. Kinga Chamber, located 195 metres below the surface, on the mine level “August”. So far measurement technologies have been connected with the studies on changes in the geometry of cavities and based on linear bases used to measure convergence. This only provides discrete information (in a point) and not always presents a real state of deformation. In the scanning method, in practice a three dimension image of changes (structural deformations) is obtained, impossible to determine with the application of measurement methods, applied to measure the value of linear convergence (the method with a limited number of bases). Laser scanning, apart from determining the value of volume convergence, gives also the possibility of the visualization of 3D cavern. Moreover, it provides direct information to update mining numerical maps and make it possible to generate various cross-sections through the cavern. The authors analysed the possibility of the application of laser scanning (scanner Faro Focus 3D), as a modern tool allowing the measuring of the value of volume convergence.

SENSITIZED FLUORESCENCE IN VAPORS OF ALKALI METALS: VIII. ENERGY TRANSFER BETWEEN THE 4 2P LEVELS IN POTASSIUM INDUCED BY INELASTIC COLLISIONS

1966 ◽  
Vol 44 (4) ◽  
pp. 753-768 ◽  
Author(s):  
G. D. Chapman ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Alkali Metals ◽  
Inelastic Collisions ◽  
Inert Gases ◽  
Inert Gas ◽  
Vapor Pressures ◽  
Sensitized Fluorescence ◽  
Potassium Vapor ◽  
The Cross ◽  
Scattering Cross Sections

Sensitized fluorescence in potassium vapor and its mixtures with inert gases was investigated in order to determine cross sections for the inelastic collisions leading to excitation transfer between the 4 2P1/2 and 4 2P3/2 states in potassium. The study was carried out at potassium vapor pressures of about 10−6 mm Hg, which were not formerly accessible to such experiments, and in the absence of radiation trapping. The cross sections Q1(4 2P1/2 → 42P3/2) and Q2(4 2P1/2 → 4 2P3/2) are as follows: for K–K collisions: 370 and 250 Å2; for K–He: 60 and 41 Å2; for K–Ne: 14 and 9.5 Å2; for K–A: 37 and 22 Å2; for K–Kr: 61 and 41 Å2; for K–Xe: 104 and 72 Å2. These values supersede those published previously (Chapman, Krause, and Brockman 1964; Chapman and Krause 1965). The cross sections for collisions between potassium and inert gas atoms do not increase monotonically with the polarizabilities of the inert gases but behave similarly to the electron – inert gas elastic scattering cross sections. This behavior is interpreted on the basis of a semiclassical model for the interaction, which involves overlap forces.

Cation Transport in Low Density Ethene and Cyclopropane Gases

1984 ◽  
Vol 39 (12) ◽  
pp. 1225-1229 ◽  
Author(s):  
Norman Gee ◽  
M. Antonio Floriano ◽  
Gordon R. Freeman
Keyword(s):  
Cross Sections ◽  
Hard Core ◽  
Cation Transport ◽  
Constant Density ◽  
Low Density ◽  
Vapor Density ◽  
Small Temperature ◽  
Applied Electric Field Strength ◽  
Dipole Interactions ◽  
Induced Dipole

Cation mobilities were independent of applied electric field strength over the range 0.06 ≦ (E/n)/Td ≦ 25 in ethene, and 0.07 ≦ (E/n)/Td ≦ 81 in cyclopropane. In the saturated vapors the density normalized mobility nμ+ was independent of vapor density over the range 0.2 ≲ n/1025 molec m-3 ≲ 80; nμ+ = (1.95 ± 0.09)/1021 molec m-1 V-1 s-1 in ethene and (1.43 ± 0.07)/1021 molec m-1 V-1 s-1 in cyclopropane. The constancy was caused by the virtual cancellation of small temperature and density effects. In the nonsaturated gases at constant density the temperature coefficient nμ+ was positive at 200 K, but decreased to near zero at 600 K. The momentum transfer cross sections σm were dominated by ion-induced dipole interactions at 0.06 ≲ ε/eV ≲ 0.2. At lower energies a softer potential, such as ion-quadrupole, made a major contribution, while at higher energies the hard core potential contributed significantly.

scholarly journals Measurement of the Energy Spectrum of 60Ni Recoils following 60Co Decay Using Nuclear Resonance Fluorescence

1976 ◽  
Vol 29 (3) ◽  
pp. 149 ◽  
Author(s):  
BD Sowerby
Keyword(s):  
Energy Spectrum ◽  
Cross Sections ◽  
Resonance Scattering ◽  
Fair Agreement ◽  
Nuclear Resonance ◽  
Resonance Fluorescence ◽  
Chemical Binding ◽  
Nuclear Resonance Fluorescence

The energy spectrum of 6�Ni recoils from 60Co fJ decay in a vapour CoBr2 source has been studied by measuring the profile of the 1� 33 MeV y rays emitted by 6�Ni. The profile was deduced from the measured cross sections for resonance scattering of the 1� 33 MeV y rays in coincidence with the preceding 1�17 MeV y rays. The results show fair agreement with the profile calculated for free 60Co atoms. The influence of molecular Coulomb fragmentation and chemical binding are discussed.

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