There is a considerable interest in the creation of vibrationally excitedH2molecules because of their application toH−volume-plasma sources, plasma chemistry etc. It was shown previously that a low-voltage discharge inCs-H2mixture might be used as an effective source of vibrationally excitedH2molecules. In the present communication, it is shown that vibrational distribution function (VDF) ofH2molecules may be very significantly improved if vibrational excitation occurs in a moving flux ofH2molecules penetrative through the discharge.The following theoretical model is considered. Hydrogen flux flows in a flat channel and passes through two sections one after another. The first section (I) is a discharge one, where low-voltageCs-H2discharge occurs and vibrationally excitedH2molecules are created. In the next section (II), the excited hydrogen flows in a plane channel, which walls are unheated. Because of a large value of the mean vibrational energy ofH2molecule, very significant intensification ofH2high vibrational level population takes place in the section II. This intensification is of the order of103−104for several vibrational levels. The increase of vibrational level population occurs due to the diffusion of vibrational quanta, by v-v exchange, up to high vibrational levels. VDF, obtained at the exit of a section II, is significantly improved for the purposes ofH−generation by means of dissociative attachment. ©1998 American Institute of Physics.