Physical Review Letters

Angular Scattering Distribution By Doppler Spectroscopy: Na(3P12)+Ar→Na(3P32)+Ar

William D. Phillips, John A. Serri, Douglas J. Ely, David E. Pritchard, Kermit R. Way, James L. Kinsey

Published Oct 2, 1978• 46 citations

Abstract

We have developed a new method for determining state-resolved differential cross sections in inelastic collisions. A single-frequency laser provides level-specific detection of scattered atoms, while the Doppler shift of the same laser provides a completely non-mechanical angular selectivity in the detection. We have used this technique to make the first measurement of an alkali fine-structure transfer cross section in which both the scattering angle and final state are determined.

DOI: 10.1103/physrevlett.41.937

Related papers

Crossed-Beam Determination of Na—Rare-Gas Fine-Structure-State—Changing Cross Sections

William D. Phillips, Charles L. Glaser, Daniel Kleppner

We report first measurements of the velocity dependence of an alkali-rare-gas fine-structure-state-changing collision with adequate range and resolution to reveal a peak in the cross section. The method uses crossed atomic beams and selective laser excitation. Results are presented for Na colliding with Ne, Ar, and Kr. The results for Na-Ar are in good agreement with theory, while those for Na-Ne and Na-Kr are in serious disagreement.

Physical Review LettersMay 2, 197735 citations

Alkali-Alkali Differential Spin-Exchange Scattering. I

David E. Pritchard, Gary M. Carter, Frank Y. Chu +1 more

Physical Review ANov 1, 197025 citations

Determination of anisotropy-dependent inelastic collision cross sections in atomic sodium using linear polarization spectroscopy

Sean Baumgartner, Simon Lauber, Servet Bayram

Physical Review ADec 7, 20124 citations

Differential cross sections of fine-structure transitions in K(4P)-He and -Ar collisions

J.‐M. Mestdagh, P. de Pujo, J. Pascale +2 more

Physical Review AFeb 1, 198710 citations

Differential cross sections for radiation assisted collisions between atoms

Joachim Großer, D Hohmeier, Selina Klose

We report angle resolved measurements of the excited Na atoms from the process with non-resonant light. The experiment provides a method to probe the NaKr collision pair by a photon. The Na( ) angular distribution shows an oscillatory structure, which can be used for a test of the NaKr potential curve system. The signal depends strongly upon the polarization of the photon. The effect provides information about the geometric properties of the collision pair.

Journal of Physics B Atomic Molecular and Optical PhysicsJan 28, 19969 citations

Evidence for hybrid classical - quantal behaviour in state- and angle-resolved atom - diatom scattering

Anthony J. McCaffery, Ruth J. Wilson

Journal of Physics B Atomic Molecular and Optical PhysicsDec 28, 199722 citations

Physical Review Letters

Angular Scattering Distribution By Doppler Spectroscopy: Na(3P12)+Ar→Na(3P32)+Ar

William D. Phillips, John A. Serri, Douglas J. Ely, David E. Pritchard, Kermit R. Way, James L. Kinsey

Published Oct 2, 1978• 46 citations

Publisher

Abstract

DOI: 10.1103/physrevlett.41.937

Related papers

Crossed-Beam Determination of Na—Rare-Gas Fine-Structure-State—Changing Cross Sections

William D. Phillips, Charles L. Glaser, Daniel Kleppner

Physical Review LettersMay 2, 197735 citations

Alkali-Alkali Differential Spin-Exchange Scattering. I

David E. Pritchard, Gary M. Carter, Frank Y. Chu +1 more

We present measurements of differential elastic cross sections for various alkali-alkali pairs, as well as the angular dependence of the probability of electron spin exchange in these collisions. The resolution is sufficient to reveal interference structure in the angular dependence of both quantities. We describe our apparatus, which polarizes one incident beam and analyzes the polarization of the scattered atoms, and discuss the measurement and data-reduction procedures. Results are presented in the range 0.1-0.2 eV for the systems Na-Cs, Na-Rb, Na-K, K-Cs, and K-Rb.We present measurements of differential elastic cross sections for various alkali-alkali pairs, as well as the angular dependence of the probability of electron spin exchange in these collisions. The resolution is sufficient to reveal interference structure in the angular dependence of both quantities. We describe our apparatus, which polarizes one incident beam and analyzes the polarization of the scattered atoms, and discuss the measurement and data-reduction procedures. Results are presented in the range 0.1-0.2 eV for the systems Na-Cs, Na-Rb, Na-K, K-Cs, and K-Rb.

Physical Review ANov 1, 197025 citations

Determination of anisotropy-dependent inelastic collision cross sections in atomic sodium using linear polarization spectroscopy

Sean Baumgartner, Simon Lauber, Servet Bayram

We report on the measurement of the linear polarization degree of the $3s{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{S}_{1/2}$ $\ensuremath{\rightarrow}$ $3p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{3/2}$ $\ensuremath{\rightarrow}$ $5s{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{S}_{1/2}$ transition in atomic sodium. A linearly polarized pump laser creates an alignment in the excited ${}^{23}$ Na $3p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{3/2}$ level. From the spectra, we extracted the inelastic collision cross section for the disalignment of the excited atoms by collisions with ground-level argon or xenon atoms. Measurements were done by monitoring the intensity of the cascade fluorescence from the $4p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{1/2}$ $\ensuremath{\rightarrow}$ $3s{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{S}_{1/2}$ transition at 330.29 nm, in the presence of Ar and Xe for pressures ranging from 5.3 to 146.6 mbar. We demonstrated that the polarization measurement can provide important information about the alignment-dependent inelastic process in alkali-metal--rare-gas collisions. A depolarization cross-section value of 196 (22) \AA{} ${}^{2}$ for Na-Ar and 357 (21) \AA{} ${}^{2}$ for Na-Xe are obtained.We report on the measurement of the linear polarization degree of the $3s{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{S}_{1/2}$ $\ensuremath{\rightarrow}$ $3p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{3/2}$ $\ensuremath{\rightarrow}$ $5s{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{S}_{1/2}$ transition in atomic sodium. A linearly polarized pump laser creates an alignment in the excited ${}^{23}$Na $3p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{3/2}$ level. From the spectra, we extracted the inelastic collision cross section for the disalignment of the excited atoms by collisions with ground-level argon or xenon atoms. Measurements were done by monitoring the intensity of the cascade fluorescence from the $4p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{1/2}$ $\ensuremath{\rightarrow}$ $3s{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{S}_{1/2}$ transition at 330.29 nm, in the presence of Ar and Xe for pressures ranging from 5.3 to 146.6 mbar. We demonstrated that the polarization measurement can provide important information about the alignment-dependent inelastic process in alkali-metal--rare-gas collisions. A depolarization cross-section value of 196 (22) \AA{}${}^{2}$ for Na-Ar and 357 (21) \AA{}${}^{2}$ for Na-Xe are obtained.

Physical Review ADec 7, 20124 citations

Differential cross sections of fine-structure transitions in K(4P)-He and -Ar collisions

J.‐M. Mestdagh, P. de Pujo, J. Pascale +2 more

Differential cross sections for the transition K(4 ${P}_{3/2}$ \ensuremath{\rightarrow}4 ${P}_{1/2}$ ) induced by He and Ar have been studied both experimentally and theoretically. Calculations were performed using a full quantal close-coupling formalism. The angular distribution of the scattered atoms is measured by Doppler shift (ADDS method). The comparison with the theoretical calculations is performed on the basis of thorough kinematic analysis. In addition, the polarization effects corresponding to the experimental conditions are taken into account carefully. This allows one to test the accuracy of various interaction potentials available for the K-He and -Ar systems. The most interesting result concerns the K-He l-dependent pseudopotentials, which are found accurate to a sufficiently high level to allow good predictions of the observed differential cross-section patterns. In particular the positions and amplitudes of the cross-section oscillations at large center-of-mass scattering angles are well reproduced. The results for Ar show that the K-Ar potentials must be improved. Finally, taking the K(4P)-He fine-structure transition as an example, it has been shown how polarization effects may be used in ADDS measurements to obtain information on the dynamics of the collision process.Differential cross sections for the transition K(4${P}_{3/2}$\ensuremath{\rightarrow}4${P}_{1/2}$) induced by He and Ar have been studied both experimentally and theoretically. Calculations were performed using a full quantal close-coupling formalism. The angular distribution of the scattered atoms is measured by Doppler shift (ADDS method). The comparison with the theoretical calculations is performed on the basis of thorough kinematic analysis. In addition, the polarization effects corresponding to the experimental conditions are taken into account carefully. This allows one to test the accuracy of various interaction potentials available for the K-He and -Ar systems. The most interesting result concerns the K-He l-dependent pseudopotentials, which are found accurate to a sufficiently high level to allow good predictions of the observed differential cross-section patterns. In particular the positions and amplitudes of the cross-section oscillations at large center-of-mass scattering angles are well reproduced. The results for Ar show that the K-Ar potentials must be improved. Finally, taking the K(4P)-He fine-structure transition as an example, it has been shown how polarization effects may be used in ADDS measurements to obtain information on the dynamics of the collision process.

Physical Review AFeb 1, 198710 citations

Differential cross sections for radiation assisted collisions between atoms

Joachim Großer, D Hohmeier, Selina Klose

Journal of Physics B Atomic Molecular and Optical PhysicsJan 28, 19969 citations

Evidence for hybrid classical - quantal behaviour in state- and angle-resolved atom - diatom scattering

Anthony J. McCaffery, Ruth J. Wilson

We present measurements of the state-to-state differential scattering cross section (DCS) for X 16Cg Na2 with Xe using a new sub-Doppler spectroscopic method and compare results with those obtained using molecular beam techniques on the same system; the agreement is good. Criteria for comparison are based on the recent finding (McCaffery A J and Wilson R J 1996 Phys. Rev. Lett. 77 48) that simple quasiclassical vector relations determine the direction of the initial relative velocity vector and the scattering angle. The incident velocity direction is such that the perpendicular component just opens the inelastic channel and the parallel component is scattered. The relationship is Newtonian but is modified by the molecule’s characteristic quantum structure. Angular distributions from a range of experiments are found to obey the vector relation, suggesting that atom–molecule collisions are controlled by a quantum-modified Newtonian mechanics, the modification arising as a consequence of the internal energy level structure of the molecule. We introduce the term quantum-constrained kinematics to describe the hybrid mechanics and suggest that this may also influence other collisional events.We present measurements of the state-to-state differential scattering cross section (DCS) for X 16Cg Na2 with Xe using a new sub-Doppler spectroscopic method and compare results with those obtained using molecular beam techniques on the same system; the agreement is good. Criteria for comparison are based on the recent finding (McCaffery A J and Wilson R J 1996 Phys. Rev. Lett. 77 48) that simple quasiclassical vector relations determine the direction of the initial relative velocity vector and the scattering angle. The incident velocity direction is such that the perpendicular component just opens the inelastic channel and the parallel component is scattered. The relationship is Newtonian but is modified by the molecule’s characteristic quantum structure. Angular distributions from a range of experiments are found to obey the vector relation, suggesting that atom–molecule collisions are controlled by a quantum-modified Newtonian mechanics, the modification arising as a consequence of the internal energy level structure of the molecule. We introduce the term quantum-constrained kinematics to describe the hybrid mechanics and suggest that this may also influence other collisional events.

Journal of Physics B Atomic Molecular and Optical PhysicsDec 28, 199722 citations

We report on the measurement of the linear polarization degree of the

3s{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{S}_{1/2}

$\ensuremath{\rightarrow}$

3p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{3/2}

$\ensuremath{\rightarrow}$

5s{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{S}_{1/2}

transition in atomic sodium. A linearly polarized pump laser creates an alignment in the excited

{}^{23}

3p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{3/2}

level. From the spectra, we extracted the inelastic collision cross section for the disalignment of the excited atoms by collisions with ground-level argon or xenon atoms. Measurements were done by monitoring the intensity of the cascade fluorescence from the

4p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{1/2}

$\ensuremath{\rightarrow}$

3s{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{S}_{1/2}

transition at 330.29 nm, in the presence of Ar and Xe for pressures ranging from 5.3 to 146.6 mbar. We demonstrated that the polarization measurement can provide important information about the alignment-dependent inelastic process in alkali-metal--rare-gas collisions. A depolarization cross-section value of 196 (22) \AA{}

{}^{2}

for Na-Ar and 357 (21) \AA{}

{}^{2}

for Na-Xe are obtained.

Differential cross sections for the transition K(4

{P}_{3/2}

\ensuremath{\rightarrow}4

{P}_{1/2}

) induced by He and Ar have been studied both experimentally and theoretically. Calculations were performed using a full quantal close-coupling formalism. The angular distribution of the scattered atoms is measured by Doppler shift (ADDS method). The comparison with the theoretical calculations is performed on the basis of thorough kinematic analysis. In addition, the polarization effects corresponding to the experimental conditions are taken into account carefully. This allows one to test the accuracy of various interaction potentials available for the K-He and -Ar systems. The most interesting result concerns the K-He l-dependent pseudopotentials, which are found accurate to a sufficiently high level to allow good predictions of the observed differential cross-section patterns. In particular the positions and amplitudes of the cross-section oscillations at large center-of-mass scattering angles are well reproduced. The results for Ar show that the K-Ar potentials must be improved. Finally, taking the K(4P)-He fine-structure transition as an example, it has been shown how polarization effects may be used in ADDS measurements to obtain information on the dynamics of the collision process.