Stimulated Raman scattering in gases and gain pressure dependence

Investigation of the CARS Spectrum of Carbon Monoxide at High Pressure and Temperature

“…They can be represented in terms of the scattering matrix (S) for inelastic energy transfer (Refs. 13,14) and certain approximations can be introduced. For example, if vibrational energy transfer rates are slo they probably are in CO, it can be shown that the off-diagonal eleme only couple transitions with the same initial and final vibrational state Thus, the G-matrix will be block diagonal, with one block for each vibrat:…”

“…If it is also assumed that the scattering matrix is on f akly dependent on vibrational state, which means that the Raman linewidths .re not dependent on vibrational band, then it can be shown that the off-diagonal element 5 kj is minus the first order rate coefficient for inelastic rotational energy transfer in the direction j -k (Refs. 13,14). Vibrational dephasing effects can arise from purely vibrational collisional processes and from rotational dephasing collisions if the effect of vibration-rotation interaction is significant.…”

Observation of the Influence of Centrifugal Distortion of the Methane Molecule on Nuclear Spin Relaxation in the Gas

“…\c and Id though at higher densities the effect of collisions is much more complex (see e.g. Ben-Reuven 1966;Alekseyev et al 1968). We shall assume (Dong and Bloom 1970) that the rotational lines are Lorentzian at low densities, i.e.…”

On the interpretation of theQ-branch of hydrogen in water

“…All the previous procedures for the calculation of the shape of the ( ) Q j branch disregarded the interference of the different transitions involved. That means, among other things, also disregarding the motional narrowing effect [12,13], that is the narrowing that is due to collisional transitions between different j states. Such an effect is not responsible for the narrowing of a single line but rather for the narrowing of a branch due to the interference effects of its lines.…”