arXiv:1411.3546 · Physical Review A

Shift and broadening of resonance lines of antiprotonic helium atoms in solid helium

A. Adamczak, D. Bakalov

Published Nov 10, 2014• 5 citations

Abstract

We have estimated the shift and broadening of the resonance lines in the spectrum of antiprotonic helium atoms $\overline{p}{\mathrm{He}}^{+}$ implanted in solid helium $^{4}\mathrm{He}$. The application of the response function for crystalline helium has enabled determination of the contributions from the collective degrees of freedom to the shift and broadening. It occurs that the broadening due to the collective motion is negligible compared to the natural line width. The available pair-correlation functions for crystalline $^{4}\mathrm{He}$ have been applied for estimating the resonance-line shift due to collisions of $\overline{p}{\mathrm{He}}^{+}$ atom with the surrounding $^{4}\mathrm{He}$ atoms. The dependence of the line shift, which has been calculated in the quasistatic limit, on the solid-$^{4}\mathrm{He}$ density is nonlinear.

DOI: 10.1103/physreva.90.054501

Related papers

Leading term of the He- p¯He+ long-range interaction

V. I. Korobov, Zhen-Xiang Zhong, Quan-Long Tian

arXiv:1509.06162Physical Review ANov 23, 201512 citations

Pressure shift and broadening of the resonance line of barium atoms in liquid helium

S. I. Kanorsky, Markus Arndt, R. Dziewior +2 more

Physical review. B, Condensed matterSep 1, 199474 citations

Anomalies in the decay rates of antiprotonic helium-atom states

H. Yamaguchi, Takashi Ishikawa, Jun Sakaguchi +8 more

Physical Review AAug 15, 200234 citations

Transitions between hyperfine structure states of antiprotonic $^4 \mathrm{He}$ at collisions with medium atoms: interaction \emph{ab initio}

Anton V. Bibikov, Grigory Ya. Korenman, S. N. Yudin

arXiv:1911.10619Nov 24, 20190 citations

Radiation width and resonance broadening in helium

Heinrich Gerhard Kuhn, Janet Maria Vaughan

Proceedings of the Royal Society of London A Mathematical and Physical SciencesFeb 11, 196460 citations

Systematic study of the decay rates of antiprotonic helium states

H. Yamaguchi, R. Hayano, Takashi Ishikawa +8 more

arXiv:physics/0401095Physical Review AJul 8, 200418 citations

arXiv:1411.3546 · Physical Review A

Shift and broadening of resonance lines of antiprotonic helium atoms in solid helium

A. Adamczak, D. Bakalov

Published Nov 10, 2014• 5 citations

arXiv HTML PDF

Abstract

We have estimated the shift and broadening of the resonance lines in the spectrum of antiprotonic helium atoms

\overline{p}{\mathrm{He}}^{+}

implanted in solid helium

^{4}\mathrm{He}

. The application of the response function for crystalline helium has enabled determination of the contributions from the collective degrees of freedom to the shift and broadening. It occurs that the broadening due to the collective motion is negligible compared to the natural line width. The available pair-correlation functions for crystalline

^{4}\mathrm{He}

have been applied for estimating the resonance-line shift due to collisions of

\overline{p}{\mathrm{He}}^{+}

atom with the surrounding

^{4}\mathrm{He}

atoms. The dependence of the line shift, which has been calculated in the quasistatic limit, on the solid-

^{4}\mathrm{He}

density is nonlinear.

DOI: 10.1103/physreva.90.054501

Related papers

Leading term of the He- p¯He+ long-range interaction

V. I. Korobov, Zhen-Xiang Zhong, Quan-Long Tian

The long-range interaction between an antiprotonic helium atom $\overline{p}{\mathrm{He}}^{+}$ and helium atom in its ground state is studied. We calculate the dispersion coefficients ${C}_{6}$ using the complex coordinate rotation (CCR) formalism in order to comply with the resonant nature of metastable states of the antiprotonic helium. We present as well numerical data on static dipole polarizabilities of antiprotonic helium states. The obtained coefficients ${C}_{6}$ may be used to estimate the collisional shift and broadening of transition lines in a low-density precision spectroscopy of the antiprotonic helium.The long-range interaction between an antiprotonic helium atom $\overline{p}{\mathrm{He}}^{+}$ and helium atom in its ground state is studied. We calculate the dispersion coefficients ${C}_{6}$ using the complex coordinate rotation (CCR) formalism in order to comply with the resonant nature of metastable states of the antiprotonic helium. We present as well numerical data on static dipole polarizabilities of antiprotonic helium states. The obtained coefficients ${C}_{6}$ may be used to estimate the collisional shift and broadening of transition lines in a low-density precision spectroscopy of the antiprotonic helium.

arXiv:1509.06162Physical Review ANov 23, 201512 citations

Pressure shift and broadening of the resonance line of barium atoms in liquid helium

S. I. Kanorsky, Markus Arndt, R. Dziewior +2 more

We have measured the pressure broadening and shift of the excitation and emission lines of the 6 ${\mathit{s}}^{2}$ $^{1}$ ${\mathit{S}}_{0}$ \ensuremath{\rightarrow}6s6p $^{1}$ ${\mathit{P}}_{1}$ transition of Ba atoms implanted in liquid and solid helium at 1.5 K. The observed spectra are quantitatively explained within the adiabatic line-broadening theory by assuming a bubble structure of the trapping sites for the Ba atoms. The evolution of the bubble shape and size in the optical excitation-deexcitation cycle is modeled theoretically.We have measured the pressure broadening and shift of the excitation and emission lines of the 6${\mathit{s}}^{2}$ $^{1}$${\mathit{S}}_{0}$\ensuremath{\rightarrow}6s6p $^{1}$${\mathit{P}}_{1}$ transition of Ba atoms implanted in liquid and solid helium at 1.5 K. The observed spectra are quantitatively explained within the adiabatic line-broadening theory by assuming a bubble structure of the trapping sites for the Ba atoms. The evolution of the bubble shape and size in the optical excitation-deexcitation cycle is modeled theoretically.

Physical review. B, Condensed matterSep 1, 199474 citations

Anomalies in the decay rates of antiprotonic helium-atom states

H. Yamaguchi, Takashi Ishikawa, Jun Sakaguchi +8 more

Six resonance transitions of the antiprotonic helium atom in helium gas at densities of $3\ifmmode\times\else\texttimes\fi{}{10}^{20}--3\ifmmode\times\else\texttimes\fi{}{10}^{21} {\mathrm{cm}}^{\ensuremath{-}3}$ were studied at the antiproton decelerator (AD) of CERN. The decay rates of the daughter states of these transitions were determined either from the time distributions of the resonance spikes or from the widths of the resonance lines. Whereas most of the observed decay rates agree with theoretical calculations of Auger rates, two states, $(n,l)=(37,33)$ and (32,31), were found to have decay rates two orders of magnitude larger than predicted by these calculations. The effect of coupling with near-lying electron-excited states is considered to be the reason for the anomaly of the (37, 33) state, as pointed out by Kartavtsev et al. [Phys. Rev. A $61,$ 062507 (2000)].Six resonance transitions of the antiprotonic helium atom in helium gas at densities of $3\ifmmode\times\else\texttimes\fi{}{10}^{20}--3\ifmmode\times\else\texttimes\fi{}{10}^{21} {\mathrm{cm}}^{\ensuremath{-}3}$ were studied at the antiproton decelerator (AD) of CERN. The decay rates of the daughter states of these transitions were determined either from the time distributions of the resonance spikes or from the widths of the resonance lines. Whereas most of the observed decay rates agree with theoretical calculations of Auger rates, two states, $(n,l)=(37,33)$ and (32,31), were found to have decay rates two orders of magnitude larger than predicted by these calculations. The effect of coupling with near-lying electron-excited states is considered to be the reason for the anomaly of the (37, 33) state, as pointed out by Kartavtsev et al. [Phys. Rev. A $61,$ 062507 (2000)].

Physical Review AAug 15, 200234 citations

Transitions between hyperfine structure states of antiprotonic $^4 \mathrm{He}$ at collisions with medium atoms: interaction \emph{ab initio}Transitions between hyperfine structure states of antiprotonic $^4 \mathrm{He}$ at collisions with medium atoms: interaction \emph{ab initio}

Anton V. Bibikov, Grigory Ya. Korenman, S. N. Yudin

Collisions of metastable antiprotonic helium atoms with atoms of the medium induce, among other processes, transitions between hyperfine structure (HFS) states, as well as shifts and broadening of microwave M1 spectral lines. In order to obtain matrix potential of interaction between $(\mathrm{\bar{p} He} ^+)$ and $\mathrm{He}$ , we have calculated the potential energy surface (PES) in the framework of unrestricted Hartree-Fock method taking into account electron correlations in the second-order perturbation theory (MP2). With this potential, the system of close-coupling equations for HFS channels is solved numerically. Cross sections and transition rates, shifts and broadening of M1 spectral lines are calculated. They are used to obtain a numerical solution of the master equation that determines the time evolution of the HFS-states density matrix. The results are compared with the experimental data and with the results of model calculation.Collisions of metastable antiprotonic helium atoms with atoms of the medium induce, among other processes, transitions between hyperfine structure (HFS) states, as well as shifts and broadening of microwave M1 spectral lines. In order to obtain matrix potential of interaction between $(\mathrm{\bar{p} He} ^+)$ and $\mathrm{He}$, we have calculated the potential energy surface (PES) in the framework of unrestricted Hartree-Fock method taking into account electron correlations in the second-order perturbation theory (MP2). With this potential, the system of close-coupling equations for HFS channels is solved numerically. Cross sections and transition rates, shifts and broadening of M1 spectral lines are calculated. They are used to obtain a numerical solution of the master equation that determines the time evolution of the HFS-states density matrix. The results are compared with the experimental data and with the results of model calculation.

arXiv:1911.10619Nov 24, 20190 citations

Radiation width and resonance broadening in helium

Heinrich Gerhard Kuhn, Janet Maria Vaughan

Abstract By means of a direct recording Fabry-Perot interferometer, the contours of several singlet lines of helium were studied over a wide range of pressure and temperature. The source was a microwave discharge cooled with liquid nitrogen or liquid helium. Analysis of the tracings allowed the Doppler and Lorentz components to be separated quantitatively. A detailed study was carried out for the line λ 7281 Å (21P - 31S). By extrapolation of the Lorentz width to zero pressure the radiation width of the level 2 was determined and led to an ƒ-value 0·377 + 0·035 of the resonance line λ 584 Å (11S— 21P) The resonance broadening is found to be independent of the speed of the atoms, over a range of a factor five in the speed, in agreement with theories of optical collision by Weisskopf and others. The absolute value of the resonance broadening constant is compared with various theories. The strong line λ 6678 Å (21P -31D) showed self-absorption due to imprisonment of resonance radiation.Abstract By means of a direct recording Fabry-Perot interferometer, the contours of several singlet lines of helium were studied over a wide range of pressure and temperature. The source was a microwave discharge cooled with liquid nitrogen or liquid helium. Analysis of the tracings allowed the Doppler and Lorentz components to be separated quantitatively. A detailed study was carried out for the line λ 7281 Å (21P - 31S). By extrapolation of the Lorentz width to zero pressure the radiation width of the level 2 was determined and led to an ƒ-value 0·377 + 0·035 of the resonance line λ 584 Å (11S— 21P) The resonance broadening is found to be independent of the speed of the atoms, over a range of a factor five in the speed, in agreement with theories of optical collision by Weisskopf and others. The absolute value of the resonance broadening constant is compared with various theories. The strong line λ 6678 Å (21P -31D) showed self-absorption due to imprisonment of resonance radiation.

Proceedings of the Royal Society of London A Mathematical and Physical SciencesFeb 11, 196460 citations

Systematic study of the decay rates of antiprotonic helium states

H. Yamaguchi, R. Hayano, Takashi Ishikawa +8 more

A systematic study of the decay rates of antiprotonic helium ( ${\overline{p}}^{4}{\mathrm{He}}^{+}$ and ${\overline{p}}^{3}{\mathrm{He}}^{+}$ ) at CERN Antiproton Decelerator has been made by a laser spectroscopic method. The decay rates of some of its short-lived states, namely those for which the Auger rates ${\ensuremath{\gamma}}_{A}$ are much larger than their radiative decay rates $({\ensuremath{\gamma}}_{\mathrm{rad}}\ensuremath{\sim}1\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}{s}^{\ensuremath{-}1})$, were determined from the time distributions of the antiproton annihilation signals induced by laser beams, and the widths of the atomic resonance lines. The magnitude of the decay rates, especially their relation with the transition multipolarity, is discussed and compared with theoretical calculations.A systematic study of the decay rates of antiprotonic helium (${\overline{p}}^{4}{\mathrm{He}}^{+}$ and ${\overline{p}}^{3}{\mathrm{He}}^{+}$) at CERN Antiproton Decelerator has been made by a laser spectroscopic method. The decay rates of some of its short-lived states, namely those for which the Auger rates ${\ensuremath{\gamma}}_{A}$ are much larger than their radiative decay rates $({\ensuremath{\gamma}}_{\mathrm{rad}}\ensuremath{\sim}1\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}{s}^{\ensuremath{-}1})$, were determined from the time distributions of the antiproton annihilation signals induced by laser beams, and the widths of the atomic resonance lines. The magnitude of the decay rates, especially their relation with the transition multipolarity, is discussed and compared with theoretical calculations.

arXiv:physics/0401095Physical Review AJul 8, 200418 citations

We have estimated the shift and broadening of the resonance lines in the spectrum of antiprotonic helium atoms

\overline{p}{\mathrm{He}}^{+}

implanted in solid helium

^{4}\mathrm{He}

^{4}\mathrm{He}

have been applied for estimating the resonance-line shift due to collisions of

\overline{p}{\mathrm{He}}^{+}

atom with the surrounding

^{4}\mathrm{He}

atoms. The dependence of the line shift, which has been calculated in the quasistatic limit, on the solid-

^{4}\mathrm{He}

density is nonlinear.

The long-range interaction between an antiprotonic helium atom

\overline{p}{\mathrm{He}}^{+}

and helium atom in its ground state is studied. We calculate the dispersion coefficients

{C}_{6}

using the complex coordinate rotation (CCR) formalism in order to comply with the resonant nature of metastable states of the antiprotonic helium. We present as well numerical data on static dipole polarizabilities of antiprotonic helium states. The obtained coefficients

{C}_{6}

may be used to estimate the collisional shift and broadening of transition lines in a low-density precision spectroscopy of the antiprotonic helium.

We have measured the pressure broadening and shift of the excitation and emission lines of the 6

{\mathit{s}}^{2}

^{1}

{\mathit{S}}_{0}

\ensuremath{\rightarrow}6s6p

^{1}

{\mathit{P}}_{1}

transition of Ba atoms implanted in liquid and solid helium at 1.5 K. The observed spectra are quantitatively explained within the adiabatic line-broadening theory by assuming a bubble structure of the trapping sites for the Ba atoms. The evolution of the bubble shape and size in the optical excitation-deexcitation cycle is modeled theoretically.

(n,l)=(37,33)

and (32,31), were found to have decay rates two orders of magnitude larger than predicted by these calculations. The effect of coupling with near-lying electron-excited states is considered to be the reason for the anomaly of the (37, 33) state, as pointed out by Kartavtsev et al. [Phys. Rev. A

61,

062507 (2000)].

Transitions between hyperfine structure states of antiprotonic

^4 \mathrm{He}

at collisions with medium atoms: interaction \emph{ab initio}

(\mathrm{\bar{p} He} ^+)

and

\mathrm{He}

, we have calculated the potential energy surface (PES) in the framework of unrestricted Hartree-Fock method taking into account electron correlations in the second-order perturbation theory (MP2). With this potential, the system of close-coupling equations for HFS channels is solved numerically. Cross sections and transition rates, shifts and broadening of M1 spectral lines are calculated. They are used to obtain a numerical solution of the master equation that determines the time evolution of the HFS-states density matrix. The results are compared with the experimental data and with the results of model calculation.

A systematic study of the decay rates of antiprotonic helium (

{\overline{p}}^{4}{\mathrm{He}}^{+}

and

{\overline{p}}^{3}{\mathrm{He}}^{+}

) at CERN Antiproton Decelerator has been made by a laser spectroscopic method. The decay rates of some of its short-lived states, namely those for which the Auger rates ${\ensuremath{\gamma}}_{A}$ are much larger than their radiative decay rates $({\ensuremath{\gamma}}_{\mathrm{rad}}\ensuremath{\sim}1\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}{s}^{\ensuremath{-}1})$, were determined from the time distributions of the antiproton annihilation signals induced by laser beams, and the widths of the atomic resonance lines. The magnitude of the decay rates, especially their relation with the transition multipolarity, is discussed and compared with theoretical calculations.