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

Journal of Physics B Atomic and Molecular Physics

Radiative collisions with impact level shifts

Edward J. Robinson

Published May 14, 1979• 7 citations
Publisher

Abstract

An analytic expression is derived for the transition probability during a radiative collision for a model problem in which induced level shifts are treated in the impulse approximation. The formulae predict a behaviour that qualitatively resembles that obtained for realistic potentials, and is in fair agreement with the experimental line shape obtained by Harris and his colleagues (1974, 1975, 1977).

DOI
10.1088/0022-3700/12/9/002

Related papers

Level-crossing expansion of laser-induced collisional energy transfer

Michele Crance, Stig Stenholm

The authors introduce a model for radiative collisions which allows one to obtain a simple analytical expression for the transition probability. This model basically consists of an improvement to the Landau-Zener model, in order to obtain a more realistic representation of the Hamiltonian of the system throughout the collision. They apply the results to the problem of radiative collisions when the dipole-dipole interaction is responsible for the energy transfer and obtain an analytical expression for the cross section as a function of the frequency and intensity of the laser field. Their results are compared with experimental results and reasonable agreement is obtained.

Journal of Physics B Atomic and Molecular Physics•Apr 28, 1980•6 citations

Theory of line-breadth phenomena

Edmond Arnous, Walter Heinrich Heitler

Abstract A general and exact formalism is developed that permits the calculation of the line shape in all line-breadth phenomena, in principle to any order of approximation. Expansions for the line breadth and the numerator occurring in the line-shape formula are given. Corrections to the classical line shape include: (i) radiative corrections to the line breadth, (ii) a level shift additional to the usual radiative shift for levels with finite transition probability, (iii) radiative corrections to the numerator and (iv) a slight frequency dependence of the numerator. All these corrections, with the exception of (iv), are exceedingly small. The case of radio-frequency transitions is discussed.

Proceedings of the Royal Society of London A Mathematical and Physical Sciences•Dec 8, 1953•20 citations

Two-photon laser-induced radiative collisions

Munir Hasan Nayfeh, G. Barry Hillard

We present a semiclassical treatment of two-photon laser-induced radiative collisions. We treat the two-photon---one-collision and two-photon---two-collision cases. We find a new intensity-induced collisional shift which makes the two-photon line shape highly sensitive to the intensity, and may make the line shape symmetric.

Physical Review A•Sep 1, 1981•10 citations

Multiphoton transitions: Approximations for the effective Hamiltonian

Leonard Rosenberg

The problem of calculating transition probabilities for an atom interacting with an intense radiation field is set up within the context of an effective Hamiltonian formalism. This has the virtue that resonance effects are properly accounted for at the outset; more generally, it provides a convenient framework for approximations. Through the restriction of the class of intermediate states to be included in the construction of the effective potential, a unitary (nonperturbative) model is obtained. A successive approximation procedure for determining the effective potential, which is based on continued-fraction representations, is described. While very likely intractable for the true problem, this successive approximation procedure can be implemented, for the model effective potential, with the aid of a generalized Rayleigh-Ritz procedure described here. The level-shift matrix is constructed from the effective potential; it determines the transition probabilities, linewidths, and energy-level displacements induced by the field. We derive variational expressions of the Kohn type for each of the elements of the model level-shift matrix.

Physical Review A•Sep 1, 1976•14 citations

Quantum Theory of Spectral Line Broadening

Stanley Bloom, Henry Margenau

Simple radiation theory is used to derive a formula proposed earlier by P. W. Anderson, for calculating the intensity within a collision-broadened spectral line. The problem is considered, first from the point of view of molecular transitions, and then by computing the work done by the light wave. The general result for absorption is stated in Eq. (18), wherein the first double integral represents true absorption, the second induced emission.

Physical Review•Jun 1, 1953•60 citations

Resonance fluorescence in radiative collisions: Theoretical study of the spectral line shapes

Roberto Buffa, M. Matera

We describe the spectral properties of the resonance fluorescence emitted in radiative collisions. The line shapes of the anelastic components of the spectrum are found to be strongly asymmetric, with extended wings related to the van der Waals shift of atomic levels. The specific case of europium and strontium atoms is considered for a combined collisional-radiative interaction following adiabatic dynamics.

Physical Review A•Nov 1, 1991•3 citations
An analytic expression is derived for the transition probability during a radiative collision for a model problem in which induced level shifts are treated in the impulse approximation. The formulae predict a behaviour that qualitatively resembles that obtained for realistic potentials, and is in fair agreement with the experimental line shape obtained by Harris and his colleagues (1974, 1975, 1977).
The authors introduce a model for radiative collisions which allows one to obtain a simple analytical expression for the transition probability. This model basically consists of an improvement to the Landau-Zener model, in order to obtain a more realistic representation of the Hamiltonian of the system throughout the collision. They apply the results to the problem of radiative collisions when the dipole-dipole interaction is responsible for the energy transfer and obtain an analytical expression for the cross section as a function of the frequency and intensity of the laser field. Their results are compared with experimental results and reasonable agreement is obtained.
Abstract A general and exact formalism is developed that permits the calculation of the line shape in all line-breadth phenomena, in principle to any order of approximation. Expansions for the line breadth and the numerator occurring in the line-shape formula are given. Corrections to the classical line shape include: (i) radiative corrections to the line breadth, (ii) a level shift additional to the usual radiative shift for levels with finite transition probability, (iii) radiative corrections to the numerator and (iv) a slight frequency dependence of the numerator. All these corrections, with the exception of (iv), are exceedingly small. The case of radio-frequency transitions is discussed.
The problem of calculating transition probabilities for an atom interacting with an intense radiation field is set up within the context of an effective Hamiltonian formalism. This has the virtue that resonance effects are properly accounted for at the outset; more generally, it provides a convenient framework for approximations. Through the restriction of the class of intermediate states to be included in the construction of the effective potential, a unitary (nonperturbative) model is obtained. A successive approximation procedure for determining the effective potential, which is based on continued-fraction representations, is described. While very likely intractable for the true problem, this successive approximation procedure can be implemented, for the model effective potential, with the aid of a generalized Rayleigh-Ritz procedure described here. The level-shift matrix is constructed from the effective potential; it determines the transition probabilities, linewidths, and energy-level displacements induced by the field. We derive variational expressions of the Kohn type for each of the elements of the model level-shift matrix.