Abstract <p>A method for calculating the radiation characteristics of diatomic atoms in the conditions of vibration–rotation nonequilibrium is proposed. The method is based on the application of the classical narrow-band k-distribution (kd) model, into which corrections for nonequilibrium are introduced. These corrections include vibrational and rotational distribution functions, as well as the Boltzmann functions averaged over vibrational and rotational temperatures. To verify the calculation technique, a series of nonequilibrium calculations has been performed, which is compared with the exact line-by-line (LBL) technique. The comparison performed in a wide range of pressures as well as translational, rotational, and vibrational temperatures has demonstrated good coincidence. Comparison of the results of calculations with experimental data has also shown satisfactory agreement.</p>