Theoretical simulation of lasers utilizing vibrational-rotational transitions in diatomic molecules allowing for anharmonicity and rotational nonequilibrium

A theoretical analysis of the operation of lasers utilizing vibrational-rotational transitions in diatomic anharmonic molecules was made taking into account the finite nature of the rotational relaxation rate. The conditions of validity of the equivalent two-level model describing these lasers were identified. Expressions for the populations of the upper and lower states participating in the lasing transition were derived using this model. Numerical calculations were made of the characteristics of an H₂–F₂ chemical laser using multilevel and two-level models and the results of the calculations were compared.