Theoretical Calculations of H(2) CARS Spectra for Propellant Flames
ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER DOVER NJ LARGE CALIBER WEAPON SYSTEMS LAB
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High energy pure rotational H2 CARS transitions have recently been observed in several spectral regions, most notably, the NO and CO CARS regions. H2 CARS is of interest because hydrogen is a major combustion product of propellants, especially nitramine propellants. For this reason, calculations were performed to assign the observed H2 transitions. For this particular case, the calculations of interest are for the observed S- and Q-branch transitions of H2 for v equal to 0 and 1. Spectroscopic constants available in the literature and the results of an ab initio calculation performed by Ermler were used in the analysis. Ermler used the potential energy curves for the ground state of hydrogen calculated by Kolos and Wolniewicz over a range of 0.4 or R or 10.0 a.u. as the basis for this calculation. The result is a set of spectroscopic constants superior to any other set examined. Having assigned the transitions, the third order susceptibility, which gives a model for data reduction of CARS spectra can be calculated. Temperature and concentration for a given species can be obtained by comparing the theoretical spectra with experimental results.
- Atomic and Molecular Physics and Spectroscopy