The transition probabilities for induced emission and absorption of electromagnetic radiation by an excited atom interacting, in addition to the radiation field, with a system of "perturbers" (in single, binary, and completed encounters) are evaluated. It is found that Dirac's result $\frac{{W}_{\mathrm{ind}}}{{W}_{\mathrm{abs}}}=\frac{({\overline{n}}_{l\ensuremath{\sigma}}+1)}{{\overline{n}}_{l\ensuremath{\sigma}}}$ must be modified by a factor $\frac{{(1\ensuremath{-}\ensuremath{\alpha}n)}^{2}}{{(1+\ensuremath{\alpha}n)}^{2}}$, where $\ensuremath{\alpha}$ is related to the interaction potential of the emitter-perturber system as well as to the level structure of the "colliding" atoms, and $n$ is the perturber number density.The transition probabilities for induced emission and absorption of electromagnetic radiation by an excited atom interacting, in addition to the radiation field, with a system of "perturbers" (in single, binary, and completed encounters) are evaluated. It is found that Dirac's result $\frac{{W}_{\mathrm{ind}}}{{W}_{\mathrm{abs}}}=\frac{({\overline{n}}_{l\ensuremath{\sigma}}+1)}{{\overline{n}}_{l\ensuremath{\sigma}}}$ must be modified by a factor $\frac{{(1\ensuremath{-}\ensuremath{\alpha}n)}^{2}}{{(1+\ensuremath{\alpha}n)}^{2}}$, where $\ensuremath{\alpha}$ is related to the interaction potential of the emitter-perturber system as well as to the level structure of the "colliding" atoms, and $n$ is the perturber number density.

Physical Review LettersNov 16, 19700 citations

Effects of Atomic Interactions on the Absorption and Emission of Radiation: The Case of Three Atoms

Helen S. Freedhoff

The Journal of Chemical PhysicsNov 15, 19714 citations

Transitions in Two-Level Systems in Atomic Collisions

E. Duman

peacJan 1, 19750 citations

Non-adiabatic effects in collision-induced radiative transitions

Henri Van Regemorter, N. Feautrier

Perturbation theory for the interaction of light with a binary collisional system is applied to the calculation of line profiles, spontaneous emission rates and absorption or stimulated emission coefficients. For the usual radiation fields are perturber densities, this approximation is valid at all detunings Delta omega except the very narrow resonance region. Appropriate expansions of the total binary system wavefunctions give the emission and absorption profiles or rates, for atom-electron systems as well as for atom-atom systems, from the impact regime at small Delta omega up to the Born-Oppenheimer regime at very large Delta omega in collision-induced radiative transitions, the transitions being asymptotically allowed or forbidden. Emphasis is given to the proper averages and sums over initial and final states of the binary system which give rise to non-adiabatic effects. One shows that it is of crucial importance to include all dynamical effects during one collisional event before undertaking any calculation at small Delta omega where simultaneous collisions may occur.Perturbation theory for the interaction of light with a binary collisional system is applied to the calculation of line profiles, spontaneous emission rates and absorption or stimulated emission coefficients. For the usual radiation fields are perturber densities, this approximation is valid at all detunings Delta omega except the very narrow resonance region. Appropriate expansions of the total binary system wavefunctions give the emission and absorption profiles or rates, for atom-electron systems as well as for atom-atom systems, from the impact regime at small Delta omega up to the Born-Oppenheimer regime at very large Delta omega in collision-induced radiative transitions, the transitions being asymptotically allowed or forbidden. Emphasis is given to the proper averages and sums over initial and final states of the binary system which give rise to non-adiabatic effects. One shows that it is of crucial importance to include all dynamical effects during one collisional event before undertaking any calculation at small Delta omega where simultaneous collisions may occur.

Journal of Physics B Atomic and Molecular PhysicsJul 14, 19859 citations

Emission Probability for a Colliding Atom

Robert William Ditchburn

Physical ReviewOct 15, 19320 citations

The binary model for collisional redistribution of light

Henri Van Regemorter

Perturbation theory for the interaction of light with a binary system is applied to collisional redistribution of radiation in the weak-field limit. Within the very large domain of validity of the binary model applied to collisions between non-hydrogenic atoms and atomic perturbers at low densities, redistribution can be viewed as collisional-induced absorption followed by spontaneous decay during a second collision. The formalism can be applied from the quasimolecular domain at large detunings Delta omega 1 or Delta omega 2 up to the impact regime, but emphasis is placed here on the non-impact region, at small Delta omega 1 or Delta omega 2, where non-adiabatic effects are important in collision-induced radiative absorption or emission rates as well as in the redistribution. The impact limit of the redistribution function is easily rederived in this way.Perturbation theory for the interaction of light with a binary system is applied to collisional redistribution of radiation in the weak-field limit. Within the very large domain of validity of the binary model applied to collisions between non-hydrogenic atoms and atomic perturbers at low densities, redistribution can be viewed as collisional-induced absorption followed by spontaneous decay during a second collision. The formalism can be applied from the quasimolecular domain at large detunings Delta omega 1 or Delta omega 2 up to the impact regime, but emphasis is placed here on the non-impact region, at small Delta omega 1 or Delta omega 2, where non-adiabatic effects are important in collision-induced radiative absorption or emission rates as well as in the redistribution. The impact limit of the redistribution function is easily rederived in this way.

Journal of Physics B Atomic and Molecular PhysicsAug 14, 19861 citation

n

is the perturber number density.