RÉSUMÉ

We present the calculation of net radiation emitted by the hottest regions of various thermal plasmas, in which we consider that the molecules are dissociated. This computation have been effected, in the pure oxygen, water, carbon dioxide and air thermal plasmas assuming isothermal and local thermodynamic equilibrium (LTE) medium, by solving the radiative transfer equation. The results show that the nature of the species has a great influence on the net emission coefficient. In spite of the strong absorption of the resonance lines, these lines constitute in general the main contribution to the total net emission.