Primordial matter cooling by molecular hydrogen

The cooling function of molecular hydrogen Λsub(Hsub(2)) under high temperatures T approximately 6000-10000 K is calculated, account being made for nonequilibrium populations of both rotational and vibrational levels at gas concentrations 1-103 cm-3. It is shown that Λsub(Hsub(2)) is influenced considerably by nonequilibrium effects caused by the difference in the mechanisms of excitation (collisions) and desactivation (mainly radiational) under the conditions when the kinetic temperature is much greater than the radiational one. The vibrational excitation of H2 was found to give the main contribution to the energy outflow and can therefore play an important role in the formation of the first generation of stars from the matter of primordial chemical composition