Chemical lasers: A thermodynamic analysis of a system in disequilibrium

The application of energy and entropy cycles to the analysis of chemical lasers is discussed and illustrated by explicit results for six reactions. Measures of the actual and the limiting efficiency (and bounds on these efficiencies) are derived and computed. In particular, it is shown that the nascent rotational excitation of the reaction products is available (on thermodynamic grounds) for lasing. The entropy changes during the different stages of lasing are computed (invoking the state property of the entropy) as the difference between the initial and final values. Explicit algorithms for computing the different entropies are provided.