Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Zeitschrift für Naturforschung A

Messung der Relaxation der Ausrichtung elektronenstoßangeregter Heliumzustände unter dem Einfluß von Eigenstößen und Kaskaden / Influence of Collisions and Cascades on the Measurement of Alignment Relaxation of Helium States Excited by Electron Impact

W. Schöck

Published Dec 1, 1972• 3 citations
Publisher

Abstract

Abstract Influence Using impact excitation, the measurement of alignment relaxation rates of atomic states is influenced by cascading transitions. The two methods for measuring the collisional depolarization, the Hanle-effect and the direct measurement of the polarization of the emitted radiation, were investigated theoretically and compared. The results were checked by measuring the depolarization of helium states excited by electron impact. The depolarization cross sections of the 3,4,5 3P-states were determined from Hanle-effect measurements as 1.8(4), 3.9(5), and 5.6(6) · 10-14 cm2 respectively.

DOI
10.1515/zna-1972-1206

Related papers

Relaxation des 5 1P1-Zustandes von Cadmium bei Stößen mit Edelgasatomen und Wasserstoffmolekülen

R. Pepperl

Abstract The linewidth of the Hanle effect signal of the orientation and alignment of the resonance level 5 1P1 of the cadmium isotop Cd114 is measured as a function of the pressure of various noble gases, of hydrogen and deuterium. The cross sections for broadening of the orientation and alignment signals due to atomic collisions are derived from the pressure dependence of the linewidth. The multipole depolarization-cross sections were found to be In order to separate the depolarization effects from quenching effects in the case of hydrogen and deuterium polarization measurements of the resonance radiation were also undertaken. The alignment depolarization- and the quenching cross sections were found to

Zeitschrift für Naturforschung A•Jun 1, 1970•10 citations

Level-Crossing-Experimente an einigen Heliumzuständen bei Ionenstoßanregung / Level-Crossing-Experiments on some He States excited by Ion Impact

K. Buchhaupt

An den Heliumzuständen 33P, 43P, 53P, 33D, 43D, 31D , 41D und 51D wurden Hanle-Effekt-Experimente bei Ionenstoßanregung mit Wasserstoff- bzw. Helium-Ionen durchgeführt. Die Breiten der Hanle-Effekt-Signale der Ausrichtung wurden in Abhängigkeit vom Heliumdruck in der Stoßkammer gemessen. Aus der Druckabhängigkeit der Signalbreiten konnten die natürlichen Lebensdauern τ0 und die Wirkungsquerschnitte σ(2) für die Zerstörung der Ausrichtung bestimmt werden. Bei Anregung durch Helium-Ionenstoß ergaben sich die Werte 33P: τ0 = 98 ± 4,3 ns, σ(2) = (2,0 ± 0,5) · 10-14 cm2, 43P: τ0 = 137 ± 9,4 ns, 53P: τ0 = 196 ± 56 ns, σ(2) = (5,3 ± 1,1) · 10-14 cm2, 33D: τ0 = 39,0 ± 1,4 ns, σ(2) = (4,6 ± 0,5) · 10-14 cm2, 43D: τ0 = 35,5 ± 1,2 ns, σ(2) = (2,9 ± 0,2) · 10-14 cm2, 31D: τ0 = 15,8 ± 0,1 ns, σ(2) = (2,4 ± 0,3) · 10-14 cm2, 41D: τ0 = 39,2 ± 0,8 ns, σ(2) = (4,8 ± 0,5) · 10-14 cm2, 51D: τ0 = 71,9 ± 1,8 ns, σ(2) = (9,6 ± 1,0) · 10-14 cm2. Aus der Abhängigkeit der Produkte ν für die Zustände 41D und 51D von der kinetischen Energie der anregenden Ionen wurde auf eine Impulsübertragung bei der Ionenstoßanregung geschlossen.

Zeitschrift für Naturforschung A•Apr 1, 1972•7 citations

Depolarization of 6P322 cesium atoms, induced in collisions with noble gases

J. Guiry, L. Krause

Cross sections for relaxation of circular and linear polarization of $6^{2}P_{\frac{3}{2}}$ cesium atoms, induced in collisions with ground-state He, Ne, Ar, and Xe, have been determined by Zeeman scanning techniques. A fluorescence cell containing low-pressure cesium vapor together with a buffer gas was irradiated with circularly or linearly polarized 8521-\AA{} Cs resonance radiation, producing excited and polarized Cs atoms which became depolarized in subsequent collisions with the buffer-gas atoms. The resulting depolarization of the cesium resonance fluorescence was monitored in relation to buffer-gas pressure (0-10 Torr) and to the strength of the ambient magnetic field (0-10 kG). At low fields at which the nuclear spin $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ is coupled to the electronic angular momentum $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$, the measurements yielded depolarization cross sections $Q(\mathrm{circ}.)$ and $Q(\mathrm{lin}.)$, which agree within experimental error with theoretical values calculated for spin-coupled conditions. At kilogauss fields with $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ and $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$ decoupled, the experiments produced cross sections for disorientation and disalignment, which are also in satisfactory agreement with the appropriate theoretical predictions. The results indicate that the nuclear spin has a more pronounced effect on the collisional relaxation of the atomic dipole than of the quadrupole.

Physical Review A•Dec 1, 1976•13 citations

Radiative lifetimes and alignment depolarization cross sections for YbI and II by the Hanle effect in a flowing helium system

Frederick H. K. Rambow, L. D. Schearer

The radiative lifetimes of the 17992-,25068-,28857-, 37414-, 40564-, and 44017-${\mathrm{cm}}^{\ensuremath{-}1}$ neutral levels and the 30392-${\mathrm{cm}}^{\ensuremath{-}1}$ ion level of Yb have been measured by the Hanle method in a fast-flowing He system. The lifetimes (in units of ${10}^{\ensuremath{-}9}$ sec) were found to be 820(20), 5.12(0.12), 14.4(0.4), 77.4(6.0), 9.32(0.6), 39.1(3.5), and 5.8(0.6), respectively. In a flowing system with He as a buffer gas the alignment depolarization cross sections with Yb were obtained and are reported here for the first time. They are (in units of ${10}^{\ensuremath{-}15}$ ${\mathrm{cm}}^{2}$) 5.0(1.0), 5.9(1.0), 5.9(1.2), 17.9(2.0), 28.2(3.0), 5.16(4.0), and 7.2(2.5), respectively.

Physical Review A•Aug 1, 1976•34 citations

Measurement of the collisional depolarization cross section of the silver 5P122 state by helium

M. Soltanolkotabr, R. Gupta

We have measured the cross section for depolarization of the $5^{2}P_{\frac{1}{2}}$ state of silver atoms by collisions with helium atoms using the Hanle-effect technique. We find the nuclear-spin-independent cross section to be $\ensuremath{\sigma}=1.2\ifmmode\pm\else\textpm\fi{}0.15\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$, significantly smaller than the corresponding cross sections in rubidium and cesium. This is the first measurement of this quantity in any noble-metal atom.

Physical Review A•Apr 1, 1984•1 citation

Pressure broadening of the Hanle effect in a neon discharge

C. Gerald Carrington, Alan Corney

Investigates the levels of the 2p 5 3p configuration of neon by studying the polarization of the light emitted by a dc neon discharge. The pressure broadening of the Hanle signals was studied and cross sections were obtained for the destruction of alignment for collisions with both helium and neon ground state atoms. The measurements have been made at 315 K and 85 K. The cross sections for the 2p 2 and 2p 6 levels (Paschen notation) change considerably with temperature, while the cross sections for other levels are almost independent of temperature.

Journal of Physics B Atomic and Molecular Physics•Jun 1, 1971•41 citations
Abstract Influence Using impact excitation, the measurement of alignment relaxation rates of atomic states is influenced by cascading transitions. The two methods for measuring the collisional depolarization, the Hanle-effect and the direct measurement of the polarization of the emitted radiation, were investigated theoretically and compared. The results were checked by measuring the depolarization of helium states excited by electron impact. The depolarization cross sections of the 3,4,5 3P-states were determined from Hanle-effect measurements as 1.8(4), 3.9(5), and 5.6(6) · 10-14 cm2 respectively.
Abstract The linewidth of the Hanle effect signal of the orientation and alignment of the resonance level 5 1P1 of the cadmium isotop Cd114 is measured as a function of the pressure of various noble gases, of hydrogen and deuterium. The cross sections for broadening of the orientation and alignment signals due to atomic collisions are derived from the pressure dependence of the linewidth. The multipole depolarization-cross sections were found to be In order to separate the depolarization effects from quenching effects in the case of hydrogen and deuterium polarization measurements of the resonance radiation were also undertaken. The alignment depolarization- and the quenching cross sections were found to
An den Heliumzuständen 33P, 43P, 53P, 33D, 43D, 31D , 41D und 51D wurden Hanle-Effekt-Experimente bei Ionenstoßanregung mit Wasserstoff- bzw. Helium-Ionen durchgeführt. Die Breiten der Hanle-Effekt-Signale der Ausrichtung wurden in Abhängigkeit vom Heliumdruck in der Stoßkammer gemessen. Aus der Druckabhängigkeit der Signalbreiten konnten die natürlichen Lebensdauern τ0 und die Wirkungsquerschnitte σ(2) für die Zerstörung der Ausrichtung bestimmt werden. Bei Anregung durch Helium-Ionenstoß ergaben sich die Werte 33P: τ0 = 98 ± 4,3 ns, σ(2) = (2,0 ± 0,5) · 10-14 cm2, 43P: τ0 = 137 ± 9,4 ns, 53P: τ0 = 196 ± 56 ns, σ(2) = (5,3 ± 1,1) · 10-14 cm2, 33D: τ0 = 39,0 ± 1,4 ns, σ(2) = (4,6 ± 0,5) · 10-14 cm2, 43D: τ0 = 35,5 ± 1,2 ns, σ(2) = (2,9 ± 0,2) · 10-14 cm2, 31D: τ0 = 15,8 ± 0,1 ns, σ(2) = (2,4 ± 0,3) · 10-14 cm2, 41D: τ0 = 39,2 ± 0,8 ns, σ(2) = (4,8 ± 0,5) · 10-14 cm2, 51D: τ0 = 71,9 ± 1,8 ns, σ(2) = (9,6 ± 1,0) · 10-14 cm2. Aus der Abhängigkeit der Produkte ν für die Zustände 41D und 51D von der kinetischen Energie der anregenden Ionen wurde auf eine Impulsübertragung bei der Ionenstoßanregung geschlossen.
Cross sections for relaxation of circular and linear polarization of 62P326^{2}P_{\frac{3}{2}}62P23​​ cesium atoms, induced in collisions with ground-state He, Ne, Ar, and Xe, have been determined by Zeeman scanning techniques. A fluorescence cell containing low-pressure cesium vapor together with a buffer gas was irradiated with circularly or linearly polarized 8521-\AA{} Cs resonance radiation, producing excited and polarized Cs atoms which became depolarized in subsequent collisions with the buffer-gas atoms. The resulting depolarization of the cesium resonance fluorescence was monitored in relation to buffer-gas pressure (0-10 Torr) and to the strength of the ambient magnetic field (0-10 kG). At low fields at which the nuclear spin $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ is coupled to the electronic angular momentum $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$, the measurements yielded depolarization cross sections Q(circ.)Q(\mathrm{circ}.)Q(circ.) and Q(lin.)Q(\mathrm{lin}.)Q(lin.), which agree within experimental error with theoretical values calculated for spin-coupled conditions. At kilogauss fields with $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ and $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$ decoupled, the experiments produced cross sections for disorientation and disalignment, which are also in satisfactory agreement with the appropriate theoretical predictions. The results indicate that the nuclear spin has a more pronounced effect on the collisional relaxation of the atomic dipole than of the quadrupole.
The radiative lifetimes of the 17992-,25068-,28857-, 37414-, 40564-, and 44017-${\mathrm{cm}}^{\ensuremath{-}1}$ neutral levels and the 30392-${\mathrm{cm}}^{\ensuremath{-}1}$ ion level of Yb have been measured by the Hanle method in a fast-flowing He system. The lifetimes (in units of ${10}^{\ensuremath{-}9}$ sec) were found to be 820(20), 5.12(0.12), 14.4(0.4), 77.4(6.0), 9.32(0.6), 39.1(3.5), and 5.8(0.6), respectively. In a flowing system with He as a buffer gas the alignment depolarization cross sections with Yb were obtained and are reported here for the first time. They are (in units of ${10}^{\ensuremath{-}15}$ cm2{\mathrm{cm}}^{2}cm2) 5.0(1.0), 5.9(1.0), 5.9(1.2), 17.9(2.0), 28.2(3.0), 5.16(4.0), and 7.2(2.5), respectively.
We have measured the cross section for depolarization of the 52P125^{2}P_{\frac{1}{2}}52P21​​ state of silver atoms by collisions with helium atoms using the Hanle-effect technique. We find the nuclear-spin-independent cross section to be $\ensuremath{\sigma}=1.2\ifmmode\pm\else\textpm\fi{}0.15\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$ cm2{\mathrm{cm}}^{2}cm2, significantly smaller than the corresponding cross sections in rubidium and cesium. This is the first measurement of this quantity in any noble-metal atom.
Investigates the levels of the 2p 5 3p configuration of neon by studying the polarization of the light emitted by a dc neon discharge. The pressure broadening of the Hanle signals was studied and cross sections were obtained for the destruction of alignment for collisions with both helium and neon ground state atoms. The measurements have been made at 315 K and 85 K. The cross sections for the 2p 2 and 2p 6 levels (Paschen notation) change considerably with temperature, while the cross sections for other levels are almost independent of temperature.