CARS study of linewidths of the Q-branch of hydrogen molecules at high temperatures in a pulsed high-pressure H2–O2 combustion chamber

The results of measurements of individual line widths of the Q-branch of a hydrogen molecule and the corresponding coefficients of broadening caused by collisions with water molecules at T = 2700 K in a repetitively pulsed high-pressure (50–200 atm) hydrogen-oxygen combustion chamber are presented. CARS spectra of individual Q₁–Q₇ hydrogen lines, pressure pulses, and the broadband CARS spectra of the entire Q-branch of hydrogen are recorded simultaneously during a single laser pulse. The shape of line profiles was analysed using a Fabry–Perot interferometer. The temperature in the volume being probed was determined from the 'broadband' CARS spectra. The entire body of the experimental results gives information on the spectral linewidths, temperature and pressure in the combustion chamber during CARS probing.