Excitation of transitions between atomic or molecular energy levels by monochromatic laser radiation. IV. Transient excitation of Doppler-broadened transitions — effect of detuning

Source abstract

Abstract The effect of detuning from the centre of the Doppler-broadened profile of a transition is studied by use of the rate of change of a modified density matrix. The variation of population density of the two energy levels involved in the transition is obtained under transient conditions. Two values of the ratio of the damping parameters 2γ and γ' for the on-diagonal and off-diagonal matrix elements are considered; γ' = γ corresponds to very low gas pressures and y' = 10y to conditions for which phase-destroying collisions predominate. While these considerations apply both in the visible and infra-red spectral regions, and equally to atoms and molecules, they are at present of special interest in connection with excitation of transitions of importance in laser photochemistry.