We show that in the Penning-ionizing collision $\mathrm{He}({2}^{3}{S}_{1})+X\ensuremath{\rightarrow}\mathrm{He}({1}^{1}{S}_{0})+{({X}^{+})}^{*}+e$ the precession of the ${\mathrm{He}}^{m}$ spin at its Larmor frequency forces the $J$ polarization of the Penning ion to rotate at the same frequency but shifted in phase. The tangent of the phase shift is proportional to the lifetime of the ionic state and presents a unique method for measuring excited-ion lifetimes.We show that in the Penning-ionizing collision $\mathrm{He}({2}^{3}{S}_{1})+X\ensuremath{\rightarrow}\mathrm{He}({1}^{1}{S}_{0})+{({X}^{+})}^{*}+e$ the precession of the ${\mathrm{He}}^{m}$ spin at its Larmor frequency forces the $J$ polarization of the Penning ion to rotate at the same frequency but shifted in phase. The tangent of the phase shift is proportional to the lifetime of the ionic state and presents a unique method for measuring excited-ion lifetimes.

Physical Review LettersAug 28, 197211 citations

Lifetime, collisional-quenching, andj-mixing measurements of the metastable 3Dlevels of Ca+

Martina Knoop, M. Vedel, F. Vedel

The metastable ${3}^{2}$ ${\mathit{D}}_{3/2,5/2}$ doublet of ${\mathrm{Ca}}^{+}$ ions stored in a Paul trap was investigated in the presence of different neutral gases, in the pressure range ${10}^{\mathrm{\ensuremath{-}}9}$--${10}^{\mathrm{\ensuremath{-}}6}$ mbar. The natural lifetimes were determined to be \ensuremath{\tau}( ${\mathit{D}}_{3/2}$ )=1111\ifmmode\pm\else\textpm\fi{}46 ms and \ensuremath{\tau}( ${\mathit{D}}_{5/2}$ )=994\ifmmode\pm\else\textpm\fi{}38 ms, which agree very well with previous experiments. The estimation of the quenching rates of ${\mathrm{Ca}}^{+}$ -He [${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{He}}$=(1.05\ifmmode\pm\else\textpm\fi{}0.42)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$], ${\mathrm{Ca}}^{+}$ -Ne [${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{}\mathrm{Ne}}$=(0.9\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$], and ${\mathrm{Ca}}^{+}$ - ${\mathrm{N}}_{2}$ [${\mathrm{\ensuremath{\Gamma}}}_{{\mathrm{N}}_{2}}$=(1.7\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$] was carried out for collisions in the energy range 0.3--1.3 eV. In addition, rate constants for the mixing of the fine-structure states were measured in the presence of helium and nitrogen for the j=3/2\ensuremath{\rightarrow}j=5/2 case [${\ensuremath{\gamma}}_{35}$(He)=(2.24\ifmmode\pm\else\textpm\fi{}0.10)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ and ${\ensuremath{\gamma}}_{35}$( ${\mathrm{N}}_{2}$ )=(2.8\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}9}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$] and for the j=5/2\ensuremath{\rightarrow}j=3/2 case [${\ensuremath{\gamma}}_{53}$(He)=(1.2\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ and ${\ensuremath{\gamma}}_{53}$( ${\mathrm{N}}_{2}$ )=(1.26\ifmmode\pm\else\textpm\fi{}0.10)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}9}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$]. The measurements were carried out populating the metastable levels by direct laser excitation of the forbidden S-D transitions.The metastable ${3}^{2}$${\mathit{D}}_{3/2,5/2}$ doublet of ${\mathrm{Ca}}^{+}$ ions stored in a Paul trap was investigated in the presence of different neutral gases, in the pressure range ${10}^{\mathrm{\ensuremath{-}}9}$--${10}^{\mathrm{\ensuremath{-}}6}$ mbar. The natural lifetimes were determined to be \ensuremath{\tau}(${\mathit{D}}_{3/2}$)=1111\ifmmode\pm\else\textpm\fi{}46 ms and \ensuremath{\tau}(${\mathit{D}}_{5/2}$)=994\ifmmode\pm\else\textpm\fi{}38 ms, which agree very well with previous experiments. The estimation of the quenching rates of ${\mathrm{Ca}}^{+}$-He [${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{He}}$=(1.05\ifmmode\pm\else\textpm\fi{}0.42)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$], ${\mathrm{Ca}}^{+}$-Ne [${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{}\mathrm{Ne}}$=(0.9\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$], and ${\mathrm{Ca}}^{+}$-${\mathrm{N}}_{2}$ [${\mathrm{\ensuremath{\Gamma}}}_{{\mathrm{N}}_{2}}$=(1.7\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$] was carried out for collisions in the energy range 0.3--1.3 eV. In addition, rate constants for the mixing of the fine-structure states were measured in the presence of helium and nitrogen for the j=3/2\ensuremath{\rightarrow}j=5/2 case [${\ensuremath{\gamma}}_{35}$(He)=(2.24\ifmmode\pm\else\textpm\fi{}0.10)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ and ${\ensuremath{\gamma}}_{35}$(${\mathrm{N}}_{2}$)=(2.8\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}9}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$] and for the j=5/2\ensuremath{\rightarrow}j=3/2 case [${\ensuremath{\gamma}}_{53}$(He)=(1.2\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ and ${\ensuremath{\gamma}}_{53}$(${\mathrm{N}}_{2}$)=(1.26\ifmmode\pm\else\textpm\fi{}0.10)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}9}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$]. The measurements were carried out populating the metastable levels by direct laser excitation of the forbidden S-D transitions.

Physical Review ANov 1, 199550 citations

Measurements of lifetimes of the excited levels in cesium and rubidium ions

Sargis Ter-Avetisyan, Valeri O. Papanyan, A.G. Maloyan

OptSpOct 1, 19960 citations

Paul–Straubel–Kingdon trap for true zero-point confinement of an individual ion and reservoir

HANS G. DEHMELT, Nan Yu

A modification of the Paul-Straubel trap previously described by us may profitably be operated in a Paul-Straubel-Kingdon (PSK) mode during the initial loading of an individual ion into the trap. Thereby the coating of the trap ring electrode by the atomic beam directed upon it in earlier experiments is eliminated, as is the ionization of an already trapped ion. Coating created serious problems as it spot-wise changed the work function of the ring electrode, which caused large, uncontrolled dc fields in the trap center that prevented zero-point confinement. Operating the Paul-Straubel trap with a small negative bias on the ring electrode wire is all that is required to realize the PSK mode. In this mode the tiny ring trap in the center of the long, straight wire section is surrounded by a second trapping well shaped like a long, thin-walled cylindrical shell and extending to the end-caps. There, ions may be conveniently created in this well without danger of coating the ring with barium. In addition, the long second well is useful as a multi-ion reservoir.A modification of the Paul-Straubel trap previously described by us may profitably be operated in a Paul-Straubel-Kingdon (PSK) mode during the initial loading of an individual ion into the trap. Thereby the coating of the trap ring electrode by the atomic beam directed upon it in earlier experiments is eliminated, as is the ionization of an already trapped ion. Coating created serious problems as it spot-wise changed the work function of the ring electrode, which caused large, uncontrolled dc fields in the trap center that prevented zero-point confinement. Operating the Paul-Straubel trap with a small negative bias on the ring electrode wire is all that is required to realize the PSK mode. In this mode the tiny ring trap in the center of the long, straight wire section is surrounded by a second trapping well shaped like a long, thin-walled cylindrical shell and extending to the end-caps. There, ions may be conveniently created in this well without danger of coating the ring with barium. In addition, the long second well is useful as a multi-ion reservoir.

Proceedings of the National Academy of SciencesSep 16, 19974 citations

Lifetime measurements with single ions and ion clouds

Martina Knoop, C. Champenois, T B Ekogo +5 more

Jan 1, 20030 citations

We show that in the Penning-ionizing collision $\mathrm{He}({2}^{3}{S}_{1})+X\ensuremath{\rightarrow}\mathrm{He}({1}^{1}{S}_{0})+{({X}^{+})}^{*}+e$ the precession of the

{\mathrm{He}}^{m}

spin at its Larmor frequency forces the

J

polarization of the Penning ion to rotate at the same frequency but shifted in phase. The tangent of the phase shift is proportional to the lifetime of the ionic state and presents a unique method for measuring excited-ion lifetimes.

The metastable

{3}^{2}

{\mathit{D}}_{3/2,5/2}

doublet of

{\mathrm{Ca}}^{+}

ions stored in a Paul trap was investigated in the presence of different neutral gases, in the pressure range ${10}^{\mathrm{\ensuremath{-}}9}$--${10}^{\mathrm{\ensuremath{-}}6}$ mbar. The natural lifetimes were determined to be \ensuremath{\tau}(

{\mathit{D}}_{3/2}

)=1111\ifmmode\pm\else\textpm\fi{}46 ms and \ensuremath{\tau}(

{\mathit{D}}_{5/2}

)=994\ifmmode\pm\else\textpm\fi{}38 ms, which agree very well with previous experiments. The estimation of the quenching rates of

{\mathrm{Ca}}^{+}

-He [${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{He}}$=(1.05\ifmmode\pm\else\textpm\fi{}0.42)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$

{\mathrm{cm}}^{3}

${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$],

{\mathrm{Ca}}^{+}

-Ne [${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{}\mathrm{Ne}}$=(0.9\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$

{\mathrm{cm}}^{3}

${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$], and

{\mathrm{Ca}}^{+}

{\mathrm{N}}_{2}

[${\mathrm{\ensuremath{\Gamma}}}_{{\mathrm{N}}_{2}}$=(1.7\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$

{\mathrm{cm}}^{3}

${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$] was carried out for collisions in the energy range 0.3--1.3 eV. In addition, rate constants for the mixing of the fine-structure states were measured in the presence of helium and nitrogen for the j=3/2\ensuremath{\rightarrow}j=5/2 case [${\ensuremath{\gamma}}_{35}$(He)=(2.24\ifmmode\pm\else\textpm\fi{}0.10)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$

{\mathrm{cm}}^{3}

${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ and ${\ensuremath{\gamma}}_{35}$(

{\mathrm{N}}_{2}

)=(2.8\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}9}$

{\mathrm{cm}}^{3}

${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$] and for the j=5/2\ensuremath{\rightarrow}j=3/2 case [${\ensuremath{\gamma}}_{53}$(He)=(1.2\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$

{\mathrm{cm}}^{3}

${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ and ${\ensuremath{\gamma}}_{53}$(

{\mathrm{N}}_{2}

)=(1.26\ifmmode\pm\else\textpm\fi{}0.10)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}9}$

{\mathrm{cm}}^{3}

${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$]. The measurements were carried out populating the metastable levels by direct laser excitation of the forbidden S-D transitions.