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

Nonimpact theory of absorption line broadening in strong radiation fields

Yitzhak Rabin, Danielle Grimbert, Shaul Mukamel

Published Jul 1, 1982• 12 citations
Publisher

Abstract

We develop an expansion for the absorption line shape of a two-level system in a strong radiation field being perturbed by dephasing collisions with a thermal bath of foreign atoms. We assume that the bath atoms do not interact with the radiation field and with each other. The microscopic information relevant for line broadening in a strong field is expressed in terms of a hierarchy of dipole correlation functions. The latter may be calculated with the use of the Franck-Condon factors for the nuclear wave functions. The present theory reduces in the weak-field limit to the well-known linear unified theory of line broadening and in the impact limit we recover the Karplus-Schwinger formula.

DOI
10.1103/physreva.26.271

Related papers

Unified theory for collisional dephasing in strong radiation fields. A generalisation of the Karplus-Schwinger formula

Yitzhak Rabin

An expansion is presented for the absorption lineshape of a two-level system in a strong radiation field being perturbed by dephasing collisions, within the binary collision approximation. No dynamical assumptions regarding the time scale of the collisions (relative to the broadening) need to be made and the present theory interpolates smoothly between the impact and the quasistatic limits. The present solution reduces in weak radiation fields to the linear unified theory of spectral lineshapes and in the impact limit (fast collisions) the authors recover the Karplus-Schwinger formula. The only molecular information necessary for the exact evaluation of the absorption lineshape in a strong field is the same single-particle correlation function g( tau ) which appears in the linear (weak field) unified theory.

Journal of Physics B Atomic and Molecular Physics•Jun 14, 1980•6 citations

Nonimpact theory of resonance Raman line shapes in strong radiation fields

Shaul Mukamel, Danielle Grimbert, Yitzhak Rabin

We develop an expansion for the resonance Raman line shape of a three-level system $|a〉$, $|b〉$, and $|c〉$ in an arbitrary strong radiation field, being perturbed by dephasing collisions with foreign gas particles. The microscopic information relevant to the line broadening is expresssed in terms of a hierarchy of $n$-time correlation functions of the transition dipole operator ($n=2,4,6,\dots{}$). To lowest order ($n=2$) the spectrum is expressed in terms of the three ordinary line-shape functions corresponding to the $\mathrm{ab}$, $\mathrm{bc}$, and $\mathrm{ac}$ transitions. The present theory is not restricted to the impact limit and, depending on the collision time scale, may yield very different results from the well-known impact spectra. Explicit calculations of the predicted spectra are presented for a model system.

Physical Review A•Jul 1, 1982•17 citations

Light absorption by a collisional system

Henri Van Regemorter

Perturbation theory is applied to the interaction between a binary collisional system and a weak radiation field to obtain the rate of induced absorption or the line profile of an optically allowed transition at low density. The collisional system wave functions are not affected by the radiation field and appropriate different expansions of these functions must be used for the two electron-atom or atom-atom systems under study. Unified expressions of the profile are given which converges to the impact limit at small detunings. The semi-classical approach of the collisional problem is given to underline the correspondence with the usual autocorrelation formalism. Both approaches break down for large detunings where a quantum collisional theory must be used.

Journal de physique•Jan 1, 1987•1 citation

Theory of collisionally aided radiative excitation

S.C. Yeh, P. R. Berman

The excitation of a two-level active atom by a radiation field in the presence of a low-density perturber bath is studied. In particular, the collisional enhancement of the absorption cross section is investigated. Features of the absorption-line profiles are predicted on physical grounds using a dressed-atom approach and verified by detailed numerical calculations for attractive, repulsive, and Lennard-Jones-type interatomic potentials. Complete spectra of the absorption cross section both as a function of detuning and as a function of field strength are given. In the weak-field limit, the results are compared with those of traditional pressure-broadening theory and to the recent experimental results of Carlsten et al. In the strong-field limit, the results display a saturation behavior consistent with the predictions of Lisitsa and Yakovlenko.

Physical Review A•Mar 1, 1979•71 citations

Non-Markovian dephasing of two-level resonance fluorescence in a strong radiation field

Zhifang Deng, Shaul Mukamel

A non-Markovian microscopic theory for the spontaneous emission spectrum of a two-level atom driven by a strong laser field and undergoing dephasing via the interaction with a thermal bath is developed. The present theory is valid for an arbitrary correlation time scale of the bath relative to the linewidth and interpolates from the Markovian to the static limits. Model calculations using the stochastic line-shape function of Kubo show how the characteristic triplet spectrum is modified by the interaction with the bath. The present results generalize our previous studies of resonance Raman scattering in a three-level system in a strong radiation field.

Physical Review A•Apr 1, 1984•9 citations

Analytic expressions for fluorescence spectra and optical collision rates of collisionally perturbed atoms in a strong driving field

F. Schuller, Gerard Nienhuis

We have studied the problem of a collisionally perturbed two-level atom in an intense driving field by developing a method which allows us to calculate the field-dependent collision operator in terms of the low intensity field-independent line-broadening function arising in the usual unified theory of pressure broadening. Our relations are exact to all orders in the field in the limiting case of weak collisions, but they are exact also in the complementary case of strong collisions and weak fields. We apply our results to derive explicit expressions for the rate of optical collisions, the fluorescence spectrum in the case of well-separated components, and the absorption during an adiabatic square pulse.

Canadian Journal of Physics•Feb 1, 1984•6 citations
We develop an expansion for the absorption line shape of a two-level system in a strong radiation field being perturbed by dephasing collisions with a thermal bath of foreign atoms. We assume that the bath atoms do not interact with the radiation field and with each other. The microscopic information relevant for line broadening in a strong field is expressed in terms of a hierarchy of dipole correlation functions. The latter may be calculated with the use of the Franck-Condon factors for the nuclear wave functions. The present theory reduces in the weak-field limit to the well-known linear unified theory of line broadening and in the impact limit we recover the Karplus-Schwinger formula.
An expansion is presented for the absorption lineshape of a two-level system in a strong radiation field being perturbed by dephasing collisions, within the binary collision approximation. No dynamical assumptions regarding the time scale of the collisions (relative to the broadening) need to be made and the present theory interpolates smoothly between the impact and the quasistatic limits. The present solution reduces in weak radiation fields to the linear unified theory of spectral lineshapes and in the impact limit (fast collisions) the authors recover the Karplus-Schwinger formula. The only molecular information necessary for the exact evaluation of the absorption lineshape in a strong field is the same single-particle correlation function g( tau ) which appears in the linear (weak field) unified theory.
We develop an expansion for the resonance Raman line shape of a three-level system ∣a〉|a〉∣a〉, ∣b〉|b〉∣b〉, and ∣c〉|c〉∣c〉 in an arbitrary strong radiation field, being perturbed by dephasing collisions with foreign gas particles. The microscopic information relevant to the line broadening is expresssed in terms of a hierarchy of nnn-time correlation functions of the transition dipole operator (n=2,4,6,…n=2,4,6,\dots{}n=2,4,6,…). To lowest order (n=2n=2n=2) the spectrum is expressed in terms of the three ordinary line-shape functions corresponding to the ab\mathrm{ab}ab, bc\mathrm{bc}bc, and ac\mathrm{ac}ac transitions. The present theory is not restricted to the impact limit and, depending on the collision time scale, may yield very different results from the well-known impact spectra. Explicit calculations of the predicted spectra are presented for a model system.
Perturbation theory is applied to the interaction between a binary collisional system and a weak radiation field to obtain the rate of induced absorption or the line profile of an optically allowed transition at low density. The collisional system wave functions are not affected by the radiation field and appropriate different expansions of these functions must be used for the two electron-atom or atom-atom systems under study. Unified expressions of the profile are given which converges to the impact limit at small detunings. The semi-classical approach of the collisional problem is given to underline the correspondence with the usual autocorrelation formalism. Both approaches break down for large detunings where a quantum collisional theory must be used.
The excitation of a two-level active atom by a radiation field in the presence of a low-density perturber bath is studied. In particular, the collisional enhancement of the absorption cross section is investigated. Features of the absorption-line profiles are predicted on physical grounds using a dressed-atom approach and verified by detailed numerical calculations for attractive, repulsive, and Lennard-Jones-type interatomic potentials. Complete spectra of the absorption cross section both as a function of detuning and as a function of field strength are given. In the weak-field limit, the results are compared with those of traditional pressure-broadening theory and to the recent experimental results of Carlsten et al. In the strong-field limit, the results display a saturation behavior consistent with the predictions of Lisitsa and Yakovlenko.
A non-Markovian microscopic theory for the spontaneous emission spectrum of a two-level atom driven by a strong laser field and undergoing dephasing via the interaction with a thermal bath is developed. The present theory is valid for an arbitrary correlation time scale of the bath relative to the linewidth and interpolates from the Markovian to the static limits. Model calculations using the stochastic line-shape function of Kubo show how the characteristic triplet spectrum is modified by the interaction with the bath. The present results generalize our previous studies of resonance Raman scattering in a three-level system in a strong radiation field.
We have studied the problem of a collisionally perturbed two-level atom in an intense driving field by developing a method which allows us to calculate the field-dependent collision operator in terms of the low intensity field-independent line-broadening function arising in the usual unified theory of pressure broadening. Our relations are exact to all orders in the field in the limiting case of weak collisions, but they are exact also in the complementary case of strong collisions and weak fields. We apply our results to derive explicit expressions for the rate of optical collisions, the fluorescence spectrum in the case of well-separated components, and the absorption during an adiabatic square pulse.