Canadian Journal of Physics

Hanle effect of the level of calcium and its density dependence

M. S. Mathur, F. M. Kelly

Published Sep 1, 1982• 8 citations

Abstract

The Hanle width and hence the lifetime of the [Formula: see text] level of neutral calcium has been measured over a wide range of densities. The natural lifetime of the [Formula: see text] level is 20.07 ns. The depolarization cross section for collision with the ground level neutral atoms has been measured and [Formula: see text].

DOI: 10.1139/p82-169

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The density dependence of the Hanle effect in the resonance line of atomic magnesium

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The Hanle width and hence the lifetime of the first excited 1P1 level of neutral magnesium have been measured over a wide range of densities. The natural lifetime of the 3s3p1P1 level is 2.00 ns. The depolarization cross section for collisions with the ground level neutral atom has been measured and [Formula: see text].

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The Hanle effect in atomic vapours produced by cathodic sputtering

E E Gibbs, Peter Hannaford

The Hanle effect has been investigated for the 4227 AA resonance line of calcium using atomic vapours produced by cathodic sputtering in a rare-gas discharge. Results are reported for the lifetime of the 4 1 P 1 state of calcium and for the alignment depolarization cross sections for the various rare gases.

Journal of Physics B Atomic and Molecular PhysicsJun 21, 197622 citations

Canadian Journal of Physics

Hanle effect of the level of calcium and its density dependence

M. S. Mathur, F. M. Kelly

Published Sep 1, 1982• 8 citations

Publisher

Abstract

DOI: 10.1139/p82-169

Related papers

The density dependence of the Hanle effect in the resonance line of atomic magnesium

F. M. Kelly, M. S. Mathur

Canadian Journal of PhysicsNov 1, 197813 citations

The density dependence of the Hanle effect in the resonance line of atomic barium

F. M. Kelly, M. S. Mathur

The change in the Hanle effect of the singlet resonance line of neutral barium has been studied over a wide range of density. The low density region has been used to confirm a lifetime of 8.37 ± 0.08 ns for the 6s6p1P1 level. We have determined the cross sections for the relaxation of the multipole moment of order 2 for collisions of the excited level with the ground level and with the metastable 6s5d1D2 level, and comparisons are made with the measured value of [Formula: see text] for the ground level with theoretical predictions.The change in the Hanle effect of the singlet resonance line of neutral barium has been studied over a wide range of density. The low density region has been used to confirm a lifetime of 8.37 ± 0.08 ns for the 6s6p1P1 level. We have determined the cross sections for the relaxation of the multipole moment of order 2 for collisions of the excited level with the ground level and with the metastable 6s5d1D2 level, and comparisons are made with the measured value of [Formula: see text] for the ground level with theoretical predictions.

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6pP2 levels of ionized barium: Lifetimes and depolarization cross sections

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The Hanle effect and its variation with density has been used to determine the depolarization cross section for collisions between the $^{2}P_{\frac{3}{2}}$ barium ions and neutral atoms. An extrapolation of the data to zero density gives a value of the average lifetime $\ensuremath{\tau}=6.22$ ns for the $6p^{2}P_{\frac{3}{2}}$ level. A further experiment gives $\ensuremath{\tau}=7.55$ ns for the $6p^{2}P_{\frac{1}{2}}$ level.The Hanle effect and its variation with density has been used to determine the depolarization cross section for collisions between the $^{2}P_{\frac{3}{2}}$ barium ions and neutral atoms. An extrapolation of the data to zero density gives a value of the average lifetime $\ensuremath{\tau}=6.22$ ns for the $6p^{2}P_{\frac{3}{2}}$ level. A further experiment gives $\ensuremath{\tau}=7.55$ ns for the $6p^{2}P_{\frac{1}{2}}$ level.

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Radiative Lifetime of the First P322 State of Ionized Calcium and Magnesium by the Hanle Effect

W. W. Smith, Alan C. Gallagher

The lifetime of the ${\mathrm{Ca}}^{+}$ $4^{2}P_{\frac{3}{2}}$ state and that of the ${\mathrm{Mg}}^{+}$ $3^{2}P_{\frac{3}{2}}$ state have been measured by the Hanle-effect method with optical excitation from the ground states of the ions. The lifetimes are, respectively, (6.72\ifmmode\pm\else\textpm\fi{}0.20)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ and (3.67\ifmmode\pm\else\textpm\fi{}0.18)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec. The ions were produced by introducing traces of calcium or magnesium into an argon discharge. "Alignment" depolarization cross sections $\ensuremath{\sigma}$ were obtained for the collisional depolarization of the following states of calcium and magnesium due to collisions with argon: $\ensuremath{\sigma}(\mathrm{Ca} 4^{1}P_{1} \mathrm{state})=(1.9\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{2};$ $\ensuremath{\sigma}({\mathrm{Ca}}^{+} 4^{2}P_{\frac{3}{2}} \mathrm{state})=(1.4\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{2};$ $\ensuremath{\sigma}(\mathrm{Mg} 3^{1}P_{1} \mathrm{state})=(1.9\ifmmode\pm\else\textpm\fi{}0.3){10}^{\ensuremath{-}14}{\mathrm{cm}}^{2};$ $\ensuremath{\sigma}({\mathrm{Mg}}^{+} 3^{2}P_{\frac{3}{2}} \mathrm{state})=(1.3\ifmmode\pm\else\textpm\fi{}0.25)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{2}.$The magnitudes of these cross sections are in accord with the theories of Byron and Foley and of Omont; we give a discussion of the extension of these theories to include ion-atom collisions.The lifetime of the ${\mathrm{Ca}}^{+}$ $4^{2}P_{\frac{3}{2}}$ state and that of the ${\mathrm{Mg}}^{+}$ $3^{2}P_{\frac{3}{2}}$ state have been measured by the Hanle-effect method with optical excitation from the ground states of the ions. The lifetimes are, respectively, (6.72\ifmmode\pm\else\textpm\fi{}0.20)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ and (3.67\ifmmode\pm\else\textpm\fi{}0.18)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec. The ions were produced by introducing traces of calcium or magnesium into an argon discharge. "Alignment" depolarization cross sections $\ensuremath{\sigma}$ were obtained for the collisional depolarization of the following states of calcium and magnesium due to collisions with argon: $\ensuremath{\sigma}(\mathrm{Ca} 4^{1}P_{1} \mathrm{state})=(1.9\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{2};$ $\ensuremath{\sigma}({\mathrm{Ca}}^{+} 4^{2}P_{\frac{3}{2}} \mathrm{state})=(1.4\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{2};$ $\ensuremath{\sigma}(\mathrm{Mg} 3^{1}P_{1} \mathrm{state})=(1.9\ifmmode\pm\else\textpm\fi{}0.3){10}^{\ensuremath{-}14}{\mathrm{cm}}^{2};$ $\ensuremath{\sigma}({\mathrm{Mg}}^{+} 3^{2}P_{\frac{3}{2}} \mathrm{state})=(1.3\ifmmode\pm\else\textpm\fi{}0.25)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{2}.$The magnitudes of these cross sections are in accord with the theories of Byron and Foley and of Omont; we give a discussion of the extension of these theories to include ion-atom collisions.

Physical ReviewMay 6, 1966136 citations

The Hanle effect in atomic vapours produced by cathodic sputtering

E E Gibbs, Peter Hannaford

Journal of Physics B Atomic and Molecular PhysicsJun 21, 197622 citations

The Hanle effect and its variation with density has been used to determine the depolarization cross section for collisions between the

^{2}P_{\frac{3}{2}}

barium ions and neutral atoms. An extrapolation of the data to zero density gives a value of the average lifetime $\ensuremath{\tau}=6.22$ ns for the

6p^{2}P_{\frac{3}{2}}

level. A further experiment gives $\ensuremath{\tau}=7.55$ ns for the

6p^{2}P_{\frac{1}{2}}

level.

The lifetime of the

{\mathrm{Ca}}^{+}

4^{2}P_{\frac{3}{2}}

state and that of the

{\mathrm{Mg}}^{+}

3^{2}P_{\frac{3}{2}}

state have been measured by the Hanle-effect method with optical excitation from the ground states of the ions. The lifetimes are, respectively, (6.72\ifmmode\pm\else\textpm\fi{}0.20)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ and (3.67\ifmmode\pm\else\textpm\fi{}0.18)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec. The ions were produced by introducing traces of calcium or magnesium into an argon discharge. "Alignment" depolarization cross sections $\ensuremath{\sigma}$ were obtained for the collisional depolarization of the following states of calcium and magnesium due to collisions with argon: $\ensuremath{\sigma}(\mathrm{Ca} 4^{1}P_{1} \mathrm{state})=(1.9\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{2};$ $\ensuremath{\sigma}({\mathrm{Ca}}^{+} 4^{2}P_{\frac{3}{2}} \mathrm{state})=(1.4\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{2};$ $\ensuremath{\sigma}(\mathrm{Mg} 3^{1}P_{1} \mathrm{state})=(1.9\ifmmode\pm\else\textpm\fi{}0.3){10}^{\ensuremath{-}14}{\mathrm{cm}}^{2};$ $\ensuremath{\sigma}({\mathrm{Mg}}^{+} 3^{2}P_{\frac{3}{2}} \mathrm{state})=(1.3\ifmmode\pm\else\textpm\fi{}0.25)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{2}.$The magnitudes of these cross sections are in accord with the theories of Byron and Foley and of Omont; we give a discussion of the extension of these theories to include ion-atom collisions.