Cooling of interstellar clouds by radiation in the rotational band of the dipole molecules

In the diffusion approximation, the rotational relaxation of diatomic dipole molecules in the rarefied gas of interstellar clouds due to collisional and radiative transitions is described. For the radiative cooling rate in the rotational band of such molecules, the analytical expressions are obtained, which can be used for the study of the energetics of the clouds in a broad interval of their parameters