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.

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.

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.

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.

scholarly journals Chip-Scale Ultra-Low Field Atomic Magnetometer Based on Coherent Population Trapping

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1517
Author(s):  
Hyun-Gue Hong ◽  
Sang Eon Park ◽  
Sang-Bum Lee ◽  
Myoung-Sun Heo ◽  
Jongcheol Park ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Ground State ◽  
Coherent Population Trapping ◽  
Zero Magnetic Field ◽  
Zero Field ◽  
Resonance Signal ◽  
Low Field ◽  
Low Magnetic Field ◽  
Population Trapping ◽  
Wide Operating

We report a chip-scale atomic magnetometer based on coherent population trapping, which can operate near zero magnetic field. By exploiting the asymmetric population among magnetic sublevels in the hyperfine ground state of cesium, we observe that the resonance signal acquires sensitivity to magnetic field in spite of degeneracy. A dispersive signal for magnetic field discrimination is obtained near-zero-field as well as for finite fields (tens of micro-tesla) in a chip-scale device of 0.94 cm3 volume. This shows that it can be readily used in low magnetic field environments, which have been inaccessible so far in miniaturized atomic magnetometers based on coherent population trapping. The measured noise floor of 300 pT/Hz1/2 at the zero-field condition is comparable to that of the conventional finite-field measurement obtained under the same conditions. This work suggests a way to implement integrated atomic magnetometers with a wide operating range.

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.

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.

scholarly journals The Mobility of H+3 and H+5 Ions in Hydrogen and the Equilibrium Constant for the Reaction H+3+2H2<=> H+5+H2 at Gas Temperatures of 195, 273 and 293 K

1974 ◽  
Vol 27 (6) ◽  
pp. 795 ◽  
Author(s):  
MT Elford ◽  
HB Milloy
Keyword(s):  
Equilibrium Constant ◽  
Zero Field ◽  
Hydrogen Ions ◽  
Mobility Data ◽  
Mass Spectrometer System ◽  
Spectrometer System ◽  
Reduced Mobility ◽  
Ion Species ◽  
Good Agreement ◽  
Gas Pressures

The mobilities of hydrogen ions in hydrogen have been measured by the Bradbury-Nielsen time-offlight method at temperatures of 195, 273 and 293 K, at pressures in the range O' 5-200 torr and at E/ N values ranging from 0�4 to 200 Td. The zero field reduced mobilities of H~ and H~ have been determined to be 1l�18�0�05 and 10'61�0'05cm2 s-1 V-1 at 293K, and 1l�18�0�05 and 10'53�0'05cm2 s-1V-1 at 273�2K respectively. At 194'5K the zero field reduced mobility of H~ was determined to be 10�40�0�05 cm2 s-1V-1 ? The thermal equilibrium constant K. for the reaction H~ + H2 + H2 +2 H~ + H2 was obtained by fitting the mobility data as a function of gas pressure. The values of K. obtained were 1�83�0�45 X 10-18, 2�8�0�7 X 10-18 and 1'6�0'6 x 10-16 cm3 at 293,273 and 195 K respectively. The reduced mobility of Hj as a function of E/N was derived for values of E/ N up to 200 Td from the data taken at gas pressures less than 2 torr and was found to be in good agreement with the data of Miller et al. (1968). The ion species present were identified by the addition of contaminants and by use of supplementary data taken with a drifttube- mass-spectrometer system. The energy for the dissociation of H~ into Hj and H2 was derived by the method of Eyring et al. (1936) and found to be 250� 50 meV.

Cross sections for quenching of Pb 6p7s3P1 atoms by collisions with CH4, CO, and CO2 molecules

1985 ◽  
Vol 63 (8) ◽  
pp. 1110-1111
Author(s):  
D. H. Giers ◽  
J. B. Atkinson ◽  
L. Krause
Keyword(s):  
Fluorescence Spectroscopy ◽  
Cross Sections ◽  
Laser Light ◽  
Buffer Gas ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Decay Constants ◽  
Gas Pressures

Pb vapor mixed with a buffer gas was irradiated with pulses of laser light so as to populate the [Formula: see text] state, whose radiative and collisional decay was monitored by the method of time-resolved fluorescence spectroscopy. The variation of the measured decay constants with buffer-gas pressures yielded the total depopulation (quenching) cross sections Q = 3.32 ± 0.25, 25.6 ± 2.2, and 84.1 ± 8.4 Å2 for collisions with CH4, CO, and CO2, respectively.

A study of radiative and collisional decay of Pb atoms by time-resolved laser spectroscopy

1984 ◽  
Vol 62 (12) ◽  
pp. 1616-1621 ◽  
Author(s):  
D. H. Giers ◽  
J. B. Atkinson ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Decay Constant ◽  
Radiative Lifetime ◽  
Resonance Wavelength ◽  
Nitrogen Laser ◽  
Buffer Gas ◽  
Time Resolved ◽  
Upper Limit ◽  
Least Squares Fit ◽  
Gas Pressures

The 6p7s[Formula: see text] state of atomic Pb was populated by irradiation of Pb vapor by the frequency-doubled output of a pulsed nitrogen laser–pumped dye laser at the resonance wavelength λ = 2833 Å, and the resulting fluorescent decay was monitored using the method of delayed coincidences. A least squares fit to the observed time-decay spectrum yielded the decay constant and gave the radiative lifetime of the [Formula: see text] state, τ = 5.85 ± 0.20 ns. The dependence of the decay constant on buffer gas pressures was also investigated, yielding the total depopulation (quenching) cross sections Q = 0.31 ± 0.10 Å2 and 12.2 ± 1.0 Å2 for collisions with H2 and N2, respectively. An upper limit (Q < 0.2 Å2) for the He quenching cross section was also determined.

scholarly journals Experimental signatures of nodeless multiband superconductivity in a $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ single crystal

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chanhee Kim ◽  
Dilip Bhoi ◽  
Yeahan Sur ◽  
Byung-Gu Jeon ◽  
Dirk Wulferding ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Zero Magnetic Field ◽  
Anisotropy Ratio ◽  
Strong Temperature Dependence ◽  
Critical Fields ◽  
Band Theory ◽  
Plane Field ◽  
Low Field ◽  
Out Of Plane

AbstractIn order to understand the superconducting gap nature of a $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ 2H-Pd 0.08 TaSe 2 single crystal with $$T_{c} = 3.13 \text { K}$$ T c = 3.13 K , in-plane thermal conductivity $$\kappa $$ κ , in-plane London penetration depth $$\lambda _{\text {L}}$$ λ L , and the upper critical fields $$H_{c2}$$ H c 2 have been investigated. At zero magnetic field, it is found that no residual linear term $$\kappa _{0}/T$$ κ 0 / T exists and $$\lambda _{\text {L}}$$ λ L follows a power-law $$T^n$$ T n (T: temperature) with n = 2.66 at $$T \le \frac{1}{3}T_c$$ T ≤ 1 3 T c , supporting nodeless superconductivity. Moreover, the magnetic-field dependence of $$\kappa _{0}$$ κ 0 /T clearly shows a shoulder-like feature at a low field region. The temperature dependent $$H_{c2}$$ H c 2 curves for both in-plane and out-of-plane field directions exhibit clear upward curvatures near $$T_c$$ T c , consistent with the shape predicted by the two-band theory and the anisotropy ratio between the $$H_{c2}$$ H c 2 (T) curves exhibits strong temperature-dependence. All these results coherently suggest that $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ 2H-Pd 0.08 TaSe 2 is a nodeless, multiband superconductor.

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