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

Bulletin of the American Physical Society

Alignment and intracollisional interference effects in slow collisions between low-Rydberg Na and ground-state He atoms

Biswajit Saha, Neal F. Lane

Published May 1, 1993• 0 citations
OpenAlex

Abstract

Semiclassical, coupled-states calculations have been performed of slow state-changing collisions between low-Rydberg (n <10) ns and np atoms and ground state He atoms. The dependence of cross sections on the initial orbital alignment of np atoms is studied. Structure in the cross sections, arising from interference between localized electron scattering (at avoided crossings), i.e., Stueckelburg oscillations, vary with the geometry (size, shape) and alignment (for non-spherical states) of the electron cloud of the initial target atom.

Related papers

Alignment and geometrical effects on Stueckelberg interference structure in cross sections for inelastic collisions involving Rydberg atoms

Bidhan C. Saha, Neal F. Lane

A theoretical study of Stueckelberg interference structure in inelastic, state-changing integrated cross sections for collisions of low-Rydberg Na (n10) atoms with ground state He atoms is reported. The dependence of the Stueckelberg interference structure on orbital geometry and alignment of the initial state is predicted. Interference oscillations are found in the cross sections for both initial ns and np states; in the latter case, the features show considerable sensitivity with respect to variations in the spatial alignment of the principal axis of the electron charge distribution at some collision velocities and near isotropy at others.

Physical Review Letters•May 30, 1994•12 citations

Relation between low-energy-electron scattering and l -changing collisions of Rydberg atoms

A. P. Hickman

Collisions of Rydberg atoms with other atoms may induce changes in the electronic orbital angular momentum of the Rydberg state. A theory is presented that expresses the cross section for this process in terms of the $s$-wave amplitude for low-energy-electron scattering from the other atom. In its most accurate form, the theory requires a convolution of the electron-scattering amplitude and the initial momentum-space wave function of the Rydberg state. However, an approximate analytic solution is derived in which the $l$-mixing cross section at a particular $n$ is written as the electron-scattering cross section at the mean electronic kinetic energy of the Rydberg state, multiplied by a scaling function that depends only on $n$. The analytic solution clearly exhibits the asymptotic scaling behavior of the cross sections. Collisions of $\mathrm{Na}(\mathrm{nd})+\mathrm{He}$, Ne, and Ar are treated as specific examples.

Physical Review A•Mar 1, 1979•55 citations

Oscillatory alignment phenomena in Rydberg-atom–rare-gas collisions

William A. Isaacs, Michael A. Morrison

Retention of orbital alignment during near-resonant energy transfer collisions of rare-gas projectiles with excited alkaline-earth-metal atoms is explored theoretically for scattering of Xe from Rydberg states of Ca. For such collisions, conventional interpretations of alignment phenomena, which are based on potential curves for a transient molecule thought to form during the collision, are not relevant. Theoretical partial magnetic sublevel cross sections for ${\mathrm{Ca}}^{**}(4s17d{}^{1}{D}_{2}\ensuremath{\rightarrow}4s18p{}^{1}{P}_{1})$ transitions confirm the existence of alignment effects, as demonstrated experimentally by Spain et al. [J. Chem. Phys. 102, 9532 (1995)], at a mean relative velocity of 914 m/s. Theory further predicts heretofore unobserved oscillatory structures in these cross sections as a function of relative velocity and that these oscillations depend strongly on the initial magnetic quantum number of the Rydberg electron.

Physical Review A•Jan 1, 1998•13 citations

Quenching of low-lying Rydberg states of Na colliding with ground-state He: A semiclassical approach

Anil Kumar, Neal F. Lane, M. Kimura

The molecular expansion method within the framework of the semiclassical approximation is applied to quenching of low-lying excited states of Rydberg atoms colliding with ground-state He at thermal energies. Interactions between the colliding atoms are accounted for in terms of pseudopotentials, and their relative motion is described by a classical linear trajectory. A fairly large basis set of Slater-type orbitals is used to obtain molecular eigenstates, and subsequently a 14-state close-coupling calculation is performed to evaluate the total quenching cross sections and the contributions of individual transitions. The energy dependence of the calculated cross sections is investigated, and possible mechanisms responsible for individual transitions are explained. Finally, the collision rates are calculated and compared with experimental results.

Physical Review A•Feb 1, 1989•21 citations

Rydberg Electron Interferometry

Michael A. Morrison, Eric G. Layton, Gregory A. Parker

A recent quantum mechanical study [W. Isaacs and M. A. Morrison, Phys. Rev. A 57, R9 (1998)] discovered pronounced oscillations in cross sections for near-resonant energy transfer collisions of rare-gas atoms with initially aligned Rydberg atoms. We analyze such collisions for 17d(m)-->18p(m(')) transitions in the Ca-He system semiclassically and show that the oscillations arise from a phase interference process unique to Rydberg target states. In addition to explaining the origin of these structures, this analysis explains their disappearance when the relative Ca-He velocity goes to infinity and/or the energy defect vanishes and their dependence on the initial and final magnetic quantum numbers of the transition.

Physical Review Letters•Feb 14, 2000•7 citations

Semiclassical calculations of thel-mixing andn,l-changing collisions of Rydberg atoms with rare-gas atoms

Владимир Сергеевич Лебедев, I. I. Fabrikant

Semiclassical calculations of the quasi-elastic l-mixing and inelastic n,l-changing processes in thermal collisions of a Rydberg sodium atom with rare-gas atoms (Ne, Ar, Kr and Xe) as well as and atoms with Ne are presented in a wide range of principal quantum numbers. The main emphasis is put on the study of the effects in the Rydberg-atom - rare-gas-atom collisions associated with both the short- and long-range (polarization) parts of the electron - perturber interaction. It is shown that the polarization interaction between the highly excited electron and the Ne atom provides the major contribution to the cross section of the l-mixing and n, l -changing transitions. We show that the Ramsauer - Townsend effect in slow electron scattering by the heavy rare-gas atoms significantly affects the values of the cross sections, particularly for the inelastic transitions with large energy transfer. A quantitative explanation of these phenomena is given using the recently developed semiclassical normalized perturbation theory for the Rydberg-atom - neutral collisions combined with the modified effective range theory for scattering of slow electrons by the rare-gas atoms.

Journal of Physics B Atomic Molecular and Optical Physics•Jun 14, 1997•19 citations
Semiclassical, coupled-states calculations have been performed of slow state-changing collisions between low-Rydberg (n <10) ns and np atoms and ground state He atoms. The dependence of cross sections on the initial orbital alignment of np atoms is studied. Structure in the cross sections, arising from interference between localized electron scattering (at avoided crossings), i.e., Stueckelburg oscillations, vary with the geometry (size, shape) and alignment (for non-spherical states) of the electron cloud of the initial target atom.
A theoretical study of Stueckelberg interference structure in inelastic, state-changing integrated cross sections for collisions of low-Rydberg Na (n10) atoms with ground state He atoms is reported. The dependence of the Stueckelberg interference structure on orbital geometry and alignment of the initial state is predicted. Interference oscillations are found in the cross sections for both initial ns and np states; in the latter case, the features show considerable sensitivity with respect to variations in the spatial alignment of the principal axis of the electron charge distribution at some collision velocities and near isotropy at others.
Collisions of Rydberg atoms with other atoms may induce changes in the electronic orbital angular momentum of the Rydberg state. A theory is presented that expresses the cross section for this process in terms of the sss-wave amplitude for low-energy-electron scattering from the other atom. In its most accurate form, the theory requires a convolution of the electron-scattering amplitude and the initial momentum-space wave function of the Rydberg state. However, an approximate analytic solution is derived in which the lll-mixing cross section at a particular nnn is written as the electron-scattering cross section at the mean electronic kinetic energy of the Rydberg state, multiplied by a scaling function that depends only on nnn. The analytic solution clearly exhibits the asymptotic scaling behavior of the cross sections. Collisions of Na(nd)+He\mathrm{Na}(\mathrm{nd})+\mathrm{He}Na(nd)+He, Ne, and Ar are treated as specific examples.
Retention of orbital alignment during near-resonant energy transfer collisions of rare-gas projectiles with excited alkaline-earth-metal atoms is explored theoretically for scattering of Xe from Rydberg states of Ca. For such collisions, conventional interpretations of alignment phenomena, which are based on potential curves for a transient molecule thought to form during the collision, are not relevant. Theoretical partial magnetic sublevel cross sections for ${\mathrm{Ca}}^{**}(4s17d{}^{1}{D}_{2}\ensuremath{\rightarrow}4s18p{}^{1}{P}_{1})$ transitions confirm the existence of alignment effects, as demonstrated experimentally by Spain et al. [J. Chem. Phys. 102, 9532 (1995)], at a mean relative velocity of 914 m/s. Theory further predicts heretofore unobserved oscillatory structures in these cross sections as a function of relative velocity and that these oscillations depend strongly on the initial magnetic quantum number of the Rydberg electron.
The molecular expansion method within the framework of the semiclassical approximation is applied to quenching of low-lying excited states of Rydberg atoms colliding with ground-state He at thermal energies. Interactions between the colliding atoms are accounted for in terms of pseudopotentials, and their relative motion is described by a classical linear trajectory. A fairly large basis set of Slater-type orbitals is used to obtain molecular eigenstates, and subsequently a 14-state close-coupling calculation is performed to evaluate the total quenching cross sections and the contributions of individual transitions. The energy dependence of the calculated cross sections is investigated, and possible mechanisms responsible for individual transitions are explained. Finally, the collision rates are calculated and compared with experimental results.
A recent quantum mechanical study [W. Isaacs and M. A. Morrison, Phys. Rev. A 57, R9 (1998)] discovered pronounced oscillations in cross sections for near-resonant energy transfer collisions of rare-gas atoms with initially aligned Rydberg atoms. We analyze such collisions for 17d(m)-->18p(m(')) transitions in the Ca-He system semiclassically and show that the oscillations arise from a phase interference process unique to Rydberg target states. In addition to explaining the origin of these structures, this analysis explains their disappearance when the relative Ca-He velocity goes to infinity and/or the energy defect vanishes and their dependence on the initial and final magnetic quantum numbers of the transition.
Semiclassical calculations of the quasi-elastic l-mixing and inelastic n,l-changing processes in thermal collisions of a Rydberg sodium atom with rare-gas atoms (Ne, Ar, Kr and Xe) as well as and atoms with Ne are presented in a wide range of principal quantum numbers. The main emphasis is put on the study of the effects in the Rydberg-atom - rare-gas-atom collisions associated with both the short- and long-range (polarization) parts of the electron - perturber interaction. It is shown that the polarization interaction between the highly excited electron and the Ne atom provides the major contribution to the cross section of the l-mixing and n, l -changing transitions. We show that the Ramsauer - Townsend effect in slow electron scattering by the heavy rare-gas atoms significantly affects the values of the cross sections, particularly for the inelastic transitions with large energy transfer. A quantitative explanation of these phenomena is given using the recently developed semiclassical normalized perturbation theory for the Rydberg-atom - neutral collisions combined with the modified effective range theory for scattering of slow electrons by the rare-gas atoms.