Measurements of CARS intensity in hydrogen molecule behind shock waves

A simple system of coherent anti-Stokes Raman Spectroscopy (CARS) consisting of a giant pulse ruby laser and a Stokes-Raman cell was used to measure the effects of temperature and pressure of the hydrogen molecule (v=O, J=1) on the intensity of the converted CARS signal. The measurements as performed behind reflected shock waves of H2-Ar mixtures in a shock tube as well as in a static cell at T=77 approximately 2,000 K, at a total pressure, p = 10 to 3rd power approximately 5 x 10 to the 5th power Pa. A semiclassical theory is developed to explain the experimental observations.