Characteristics of the changes in the refractive index due to interaction of a radiation pulse with an inverted medium

Grabovskii, V. I.; Starik, A. M.

doi:10.1070/qe1994v024n04abeh000088

Cited by 5 publications

(4 citation statements)

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“…Thus, we can ignore the variation in the parameters in the longitudinal direction compared to their variation across the beam and consider an optically thin gas layer. In this case, the variation in the hydrodynamic quantities and concentrations of the components is determined by the hierarchy of the characteristic times of various macro and microtransfer processes [14,15]. For a reactive gas in vibrational nonequilibrium, these are the times of the following processes: induced transitions (τ I ); the energy relaxation of vibrationally excited states (τ VT ); the radiation-pulse duration (τ p ); the chemical reaction resulting in formation of the component determining the igniting mechanism of the mixture (τ ch i,q ); the propagation of acoustic vibrations across the beam (τ a ), the multicomponent (τ D,i ) and thermal diffusion of the ith component (τ T,i ); the vibrational thermal diffusion (τ V D,i ); heat conduction (τ λ ); vibrational thermal conduction of the jth oscillator (τ V,j ); convection due to viscosity (τ c ); the state transition of the medium due to the striction force (τ F ).…”

Section: Formulation Of the Problem And Basic Assumptionsmentioning

confidence: 99%

Activation of Chain Processes in Combustible Mixtures by Laser Excitation of Molecular Vibrations of Reactants

Lukhovitskii

Starik

Титова

2005

Combust Explos Shock Waves

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The combustion kinetics of H 2 -air mixtures containing small amounts (<1%) of ozone is analyzed for the case of excitation of asymmetric vibrations of O 3 molecules by CO 2 laser radiation with a wavelength of ≈9.7 µm. It is shown that the irradiation leads to acceleration of the collisional dissociation of O 3 molecules, activation of the chain ignition mechanism, and a decrease in the induction period and ignition temperature. The excitation of asymmetric vibrations of O 3 molecules by the CO 2 laser radiation is 10-10 3 times more effective than the currently used method of combustion initiation based on local heating of a medium by IR radiation.

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Section: Formulation Of the Problem And Basic Assumptionsmentioning

confidence: 99%

Activation of Chain Processes in Combustible Mixtures by Laser Excitation of Molecular Vibrations of Reactants

Lukhovitskii

Starik

Титова

2005

Combust Explos Shock Waves

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“…This is due to the contribution of nuclear motion and the effect of an electric field on the vibrational wave function [14][15][16]. This can lead to a change in the refractive index of molecular gas [17][18][19] and self-focusing of an intense laser beam in a gaseous medium [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Influence of vibrations and rotations of diatomic molecules on their physical properties: I. Dipole moment and static dipole polarizability

Loukhovitski

Sharipov

Starik

2016

J. Phys. B: At. Mol. Opt. Phys.

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Electronic dipole moment and static polarizability functions for some diatomic molecules (H2, N2, O2, NO, OH, CO, CH, HF and HCl) that are important for combustion and atmospheric chemistry are calculated by using ab initio methods over a broad range of internuclear distances. Using the ab initio calculated data on the electric properties and potential energy functions, the effective values of dipole moment and static polarizability as well as the energy levels of these molecules in individual vibrational and rotational states until the dissociation threshold are determined. It is revealed that, for the ground electronic states of molecules under study, the excitation of molecule vibrations can affect the averaged dipole moment and static polarizability substantially, whereas the effect of excitation of the rotational states is less pronounced.

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Section: Formulation Of the Problem And Governing Equationsmentioning

confidence: 99%

Initiation of combustion by laser-induced excitation of molecular vibrations of reactants

2006

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The features of combustion initiation in H 2 /air and CH 4 (C 2 H 2 )/air mixtures under laser-induced excitation of the asymmetric mode of ozone molecules added in a small amount to the mixture are analyzed. It was shown that such an approach to supply radiation energy to the combustible mixtures reduces the induction time and decreases the ignition temperature at a small energy of laser radiation delivered to the mixture. These effects are explained mostly by two factors -the intensification of chain reactions due to acceleration of O-atom formation during dissociation of vibrationally excited O 3 molecules and the heating of the mixture due to a faster decomposition of O 3 molecules. The considered method of ignition/combustion control is much more effective (by a factor of 10-100) than the method based on heating the gas by resonance laser radiation in the case where the characteristic time of highly reactive radical and atom formation does not exceed significantly the relaxation time of the asymmetric mode of the O 3 molecule.

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Characteristics of the changes in the refractive index due to interaction of a radiation pulse with an inverted medium

Cited by 5 publications

References 0 publications

Activation of Chain Processes in Combustible Mixtures by Laser Excitation of Molecular Vibrations of Reactants

Activation of Chain Processes in Combustible Mixtures by Laser Excitation of Molecular Vibrations of Reactants

Influence of vibrations and rotations of diatomic molecules on their physical properties: I. Dipole moment and static dipole polarizability

Initiation of combustion by laser-induced excitation of molecular vibrations of reactants

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