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

Physical Review A

Collisional redistribution in Hg-Kr: Polarization spectrum of the redistributed light

I. M. Bell, C. J. K. Quayle, Keith R. Burnett, D. M. Segal

Published Apr 1, 1993• 8 citations
Publisher

Abstract

We have measured the alignment of Hg(6 $^{3}$${\mathit{P}}_{1}$) atoms following off-resonant excitation of the Hg 6 $^{1}\mathrm{S}_{0}$--6 $^{3}\mathrm{P}_{1}$ transition in the presence of Kr. We present a polarization spectrum for both red and blue wings out to detunings beyond 100 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. This represents a considerable extension to the existing results, which has been made possible by the use of a pump-and-probe excitation scheme. In the experiment a pulsed laser, detuned from the resonance, creates an alignment in the upper state. This is probed by tuning a delayed second laser to a higher transition and monitoring laser-induced fluorescence from the two-step process. The alignment of the asymptotic Hg(6 $^{3}$${\mathit{P}}_{1}$) atoms is determined by comparison of the signals obtained for different relative polarizations of the lasers. We discuss the advantages of this method and the relation of the raw data to the polarizations presented. The results are discussed within the context of a simple quasiclassical model of the process.

DOI
10.1103/physreva.47.3128

Related papers

Polarisation-monitored collisional redistribution experiment in Hg(3P1-1S0)-Kr

D Segal, Keith R. Burnett

The authors have measured the polarisation of collisionally redistributed light as a function of detuning from line centre for the Hg 3 P 1 - 1 S 0 transition in the presence of Kr. These are the first such results for a J=0 to 1 system for which the interatomic potentials are well documented. They present a polarisation profile for the red wing between 5 and 40 cm -1 and polarisation measurements for two individual detunings in the blue wing. The data have been corrected for various mechanisms which affect the polarisation but which do not depend on the original scattering event. The application of some of these corrections has been discussed elsewhere for the CW case. Since they report the first pulsed collisional redistribution experiments involving depolarisation measurements they discuss the differences between the pulsed and CW cases in detail.

Journal of Physics B Atomic Molecular and Optical Physics•Jan 28, 1989•10 citations

Coherence effects in half collisions: Collision induced fluorescence in Hg(2537 Å)–Ar

D. Segal, I. D. Harris

We have measured the polarization of collisionally redistributed light as a function of detuning from line center for the Hg3P1–1S0 transition in the presence of Ar. We present a polarization profile for the red wing between 5 and 18 cm−1 and polarizations for two detunings in the blue wing. We compare this type of experiment to the complementary method of photodissociation and discuss the issue of coherence between excitation path-ways. The data are analyzed using a simple molecular reorientation model suggested by others which includes coherent excitation. The model is shown to be unable to completely account for the high polarizations measured in this experiment. We suggest reasons for the failure of this model.

The Journal of Chemical Physics•Feb 15, 1991•10 citations

Collisional redistribution of light: Far-wing line shapes and polarizations for the Ba-(Ar,Xe) systems

W. J. Alford, N. Andersen, Keith R. Burnett +1 more

We have measured the far-wing collisional redistribution line shape, the redistributed fluorescence polarization, and the collisional alignment decay rates for barium perturbed by argon and xenon. The experiment was performed with a heated gas cell ($T\ensuremath{\sim}900$ K) with perturber-gas densities in the 1---30-Torr range and laser light detuned \ifmmode\pm\else\textpm\fi{} 3--- 1000 ${\mathrm{cm}}^{\ensuremath{-}1}$ from the 5535-\AA{} Ba I $6^{1}S\ensuremath{-}6^{1}P$ resonance line. Metal-vapor densities were determined by a Rayleigh scattering technique, which is outlined in detail. By correlating structure in the line shape with that of the polarization, we are able to make definitive statements about the interatomic potentials. The Ba data show strong similarities with previous experimental results for similar two-electron atoms, namely Ca, Sr, and Hg, and so our conclusions are of relevance to these systems as well.

Physical Review A•Nov 1, 1984•87 citations

Polarization spectra of excited-state-Mg(3p)–rare-gas-atom optical collisions

Rosemary A. Lasell, D. A. Olsgaard, Mark D. Havey +1 more

Experimental, polarization-dependent excitation spectra for excited-state-Mg--rare-gas-atom optical collisions are reported. In these first studies of the process, polarized Mg atoms in the 3p $^{1}$${\mathit{P}}_{1}$ level are produced by absorption of linearly polarized light tuned to the 3s $^{1}$${\mathit{S}}_{0}$\ensuremath{\rightarrow}3p $^{1}$${\mathit{P}}_{1}$ resonance transition at 285.2 nm. Detuning-dependent, collision-induced polarization spectra are measured in a \ifmmode\pm\else\textpm\fi{}200-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ range around the Mg 3p $^{1}$${\mathit{P}}_{1}$\ensuremath{\rightarrow}5s $^{1}$${\mathit{S}}_{0}$ transition at 571.2 nm. The spectra correspond to probing transient Mg-Ne and Mg-Ar molecules on 3p $^{1}\mathrm{\ensuremath{\Pi}}_{1}$\ensuremath{\rightarrow}5s $^{1}\mathrm{\ensuremath{\Sigma}}_{0}^{+}$ and 3p $^{1}\mathrm{\ensuremath{\Sigma}}_{0}^{+}$\ensuremath{\rightarrow}5s $^{1}\mathrm{\ensuremath{\Sigma}}_{0}^{+}$ electronic transitions. Measurements of these excited-state polarization spectra for Mg-Ne optical collisions reveal that for detunings to the red of the atomic Mg 3p $^{1}$${\mathit{P}}_{1}$\ensuremath{\rightarrow}5s $^{1}$${\mathit{S}}_{0}$ transition, electronic linear polarization greater than 50% survives far into the molecular regime. This represents a direct measure of the polarization important to alignment-dependent inelastic processes in alkaline-earth-metal--rare-gas-atom collisions. The polarization spectra are discussed in terms of existing information on the interatomic potentials and through an axial recoil limit for the polarization degree for parallel and perpendicular molecular transitions. Rate coefficients k for disalignment of Mg 3p $^{1}$${\mathit{P}}_{1}$ atoms by collisions with Ar [k=9.4(5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$/s] and with Ne [k=6.5(7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$/s] are also extracted from the data.

Physical Review A•Jul 1, 1994•9 citations

Alignment of Hg–Ar van der Waals molecule photofragments following photodissociation

C. J. K. Quayle, I. M. Bell, Endre Takács +3 more

We have measured the alignment of the photofragments produced by photodissociation of Hg–Ar van der Waals molecules using light around 253.7 nm. The molecules are produced in the X0+ ground state in a supersonic expansion. Tunable laser light close to the Hg 6 1S0–6 3P1 transition is then used to excite the molecule to the B1± state, in which it dissociates. The alignment of the resulting Hg(3P1) asymptotic atoms is probed by tuning a delayed second laser to the 435.8 nm Hg 6 3P1–7 3S1 atomic transition and monitoring the subsequent fluorescence on the 7 3S1–6 3P2 transition around 546.1 nm. These measurements have been made, we believe for the first time, as a function of dissociating energy from very close to threshold to higher energies. The alignment shows a significant rise with increasing photon energy in line with a semiclassical picture of orbital locking at lower energies and rapid decoupling at higher energies. The results exhibit good agreement with the results of a fully quantum mechanical theory of the system.

The Journal of Chemical Physics•Dec 15, 1993•19 citations

Hyperfine structure effects in probing atomic alignment

I. M. Bell, C. J. K. Quayle, Keith R. Burnett

We have performed an analysis of the effect of hyperfine structure in an experiment in which an aligned excited state is probed using linearly polarized light. The state is born with a given electronic alignment resulting from a collisional process. It is probed after a time which is short in comparison to its radiative lifetime but much longer than ω−1hfs, where ℏωhfs is the hyperfine splitting. This means that hyperfine structure has ample time to ‘‘develop.’’ It is therefore essential to take into account both the hyperfine structure of the level and the manner in which the alignment is affected by recoupling to the new basis. Ratios of fluorescent intensities for different laser polarization configurations contain information on the alignment of the system. We show how these may be calculated for a system with several isotopes, some of which have hyperfine structure, and where many components are probed with appreciable strength. A comparison is made with our experimental results for the Hg(6 3P1) level probed on the 6 3P1–7 3S1 transition. The presence of hyperfine structure has a considerable influence on the measurements. It is important to understand such effects if one is to obtain information on the nascent electronic alignment by observation of the fluorescent intensities.

The Journal of Chemical Physics•Feb 1, 1995•1 citation
We have measured the alignment of Hg(6 ^{3}$${\mathit{P}}_{1}) atoms following off-resonant excitation of the Hg 6 1S0^{1}\mathrm{S}_{0}1S0​--6 3P1^{3}\mathrm{P}_{1}3P1​ transition in the presence of Kr. We present a polarization spectrum for both red and blue wings out to detunings beyond 100 cm\ensuremath−1{\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}cm\ensuremath−1. This represents a considerable extension to the existing results, which has been made possible by the use of a pump-and-probe excitation scheme. In the experiment a pulsed laser, detuned from the resonance, creates an alignment in the upper state. This is probed by tuning a delayed second laser to a higher transition and monitoring laser-induced fluorescence from the two-step process. The alignment of the asymptotic Hg(6 ^{3}$${\mathit{P}}_{1}) atoms is determined by comparison of the signals obtained for different relative polarizations of the lasers. We discuss the advantages of this method and the relation of the raw data to the polarizations presented. The results are discussed within the context of a simple quasiclassical model of the process.
The authors have measured the polarisation of collisionally redistributed light as a function of detuning from line centre for the Hg 3 P 1 - 1 S 0 transition in the presence of Kr. These are the first such results for a J=0 to 1 system for which the interatomic potentials are well documented. They present a polarisation profile for the red wing between 5 and 40 cm -1 and polarisation measurements for two individual detunings in the blue wing. The data have been corrected for various mechanisms which affect the polarisation but which do not depend on the original scattering event. The application of some of these corrections has been discussed elsewhere for the CW case. Since they report the first pulsed collisional redistribution experiments involving depolarisation measurements they discuss the differences between the pulsed and CW cases in detail.
We have measured the polarization of collisionally redistributed light as a function of detuning from line center for the Hg3P1–1S0 transition in the presence of Ar. We present a polarization profile for the red wing between 5 and 18 cm−1 and polarizations for two detunings in the blue wing. We compare this type of experiment to the complementary method of photodissociation and discuss the issue of coherence between excitation path-ways. The data are analyzed using a simple molecular reorientation model suggested by others which includes coherent excitation. The model is shown to be unable to completely account for the high polarizations measured in this experiment. We suggest reasons for the failure of this model.
We have measured the far-wing collisional redistribution line shape, the redistributed fluorescence polarization, and the collisional alignment decay rates for barium perturbed by argon and xenon. The experiment was performed with a heated gas cell ($T\ensuremath{\sim}900$ K) with perturber-gas densities in the 1---30-Torr range and laser light detuned \ifmmode\pm\else\textpm\fi{} 3--- 1000 ${\mathrm{cm}}^{\ensuremath{-}1}$ from the 5535-\AA{} Ba I $6^{1}S\ensuremath{-}6^{1}P$ resonance line. Metal-vapor densities were determined by a Rayleigh scattering technique, which is outlined in detail. By correlating structure in the line shape with that of the polarization, we are able to make definitive statements about the interatomic potentials. The Ba data show strong similarities with previous experimental results for similar two-electron atoms, namely Ca, Sr, and Hg, and so our conclusions are of relevance to these systems as well.
Experimental, polarization-dependent excitation spectra for excited-state-Mg--rare-gas-atom optical collisions are reported. In these first studies of the process, polarized Mg atoms in the 3p 1^{1}1P1{\mathit{P}}_{1}P1​ level are produced by absorption of linearly polarized light tuned to the 3s 1^{1}1S0{\mathit{S}}_{0}S0​\ensuremath{\rightarrow}3p 1^{1}1P1{\mathit{P}}_{1}P1​ resonance transition at 285.2 nm. Detuning-dependent, collision-induced polarization spectra are measured in a \ifmmode\pm\else\textpm\fi{}200-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ range around the Mg 3p 1^{1}1P1{\mathit{P}}_{1}P1​\ensuremath{\rightarrow}5s 1^{1}1S0{\mathit{S}}_{0}S0​ transition at 571.2 nm. The spectra correspond to probing transient Mg-Ne and Mg-Ar molecules on 3p $^{1}\mathrm{\ensuremath{\Pi}}_{1}$\ensuremath{\rightarrow}5s $^{1}\mathrm{\ensuremath{\Sigma}}_{0}^{+}$ and 3p $^{1}\mathrm{\ensuremath{\Sigma}}_{0}^{+}$\ensuremath{\rightarrow}5s $^{1}\mathrm{\ensuremath{\Sigma}}_{0}^{+}$ electronic transitions. Measurements of these excited-state polarization spectra for Mg-Ne optical collisions reveal that for detunings to the red of the atomic Mg 3p 1^{1}1P1{\mathit{P}}_{1}P1​\ensuremath{\rightarrow}5s 1^{1}1S0{\mathit{S}}_{0}S0​ transition, electronic linear polarization greater than 50% survives far into the molecular regime. This represents a direct measure of the polarization important to alignment-dependent inelastic processes in alkaline-earth-metal--rare-gas-atom collisions. The polarization spectra are discussed in terms of existing information on the interatomic potentials and through an axial recoil limit for the polarization degree for parallel and perpendicular molecular transitions. Rate coefficients k for disalignment of Mg 3p 1^{1}1P1{\mathit{P}}_{1}P1​ atoms by collisions with Ar [k=9.4(5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ cm3{\mathrm{cm}}^{3}cm3/s] and with Ne [k=6.5(7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ cm3{\mathrm{cm}}^{3}cm3/s] are also extracted from the data.
We have measured the alignment of the photofragments produced by photodissociation of Hg–Ar van der Waals molecules using light around 253.7 nm. The molecules are produced in the X0+ ground state in a supersonic expansion. Tunable laser light close to the Hg 6 1S0–6 3P1 transition is then used to excite the molecule to the B1± state, in which it dissociates. The alignment of the resulting Hg(3P1) asymptotic atoms is probed by tuning a delayed second laser to the 435.8 nm Hg 6 3P1–7 3S1 atomic transition and monitoring the subsequent fluorescence on the 7 3S1–6 3P2 transition around 546.1 nm. These measurements have been made, we believe for the first time, as a function of dissociating energy from very close to threshold to higher energies. The alignment shows a significant rise with increasing photon energy in line with a semiclassical picture of orbital locking at lower energies and rapid decoupling at higher energies. The results exhibit good agreement with the results of a fully quantum mechanical theory of the system.
We have performed an analysis of the effect of hyperfine structure in an experiment in which an aligned excited state is probed using linearly polarized light. The state is born with a given electronic alignment resulting from a collisional process. It is probed after a time which is short in comparison to its radiative lifetime but much longer than ω−1hfs, where ℏωhfs is the hyperfine splitting. This means that hyperfine structure has ample time to ‘‘develop.’’ It is therefore essential to take into account both the hyperfine structure of the level and the manner in which the alignment is affected by recoupling to the new basis. Ratios of fluorescent intensities for different laser polarization configurations contain information on the alignment of the system. We show how these may be calculated for a system with several isotopes, some of which have hyperfine structure, and where many components are probed with appreciable strength. A comparison is made with our experimental results for the Hg(6 3P1) level probed on the 6 3P1–7 3S1 transition. The presence of hyperfine structure has a considerable influence on the measurements. It is important to understand such effects if one is to obtain information on the nascent electronic alignment by observation of the fluorescent intensities.