Some gas phase irradiations under continuous wave infrared conditions [CW laser] and pulsed ultraviolet conditions [ArF excimer laser.] are presented. The amount of energy absorbed by CO2-the gas phase system irradiated by a CW CO2) laser of several hundreds watts of output power, depends essentially on the thermodiffusivity of the absorbet. Therefore this parameter affects dramatically the overall decomposition kinetic of any species irradiated by a powerful infrared laser. With binary gas mixtures of absorber coupled with reactant, in the conditions of a photo sensitized decomposition, the distribution of the energy which is captured, between the two partners, leads to a maximum reaction rate at a given pressure of reactant. When the ultraviolet laser irradiation of various species at 193.3 nm is assisted by a CW infrared irradiation,different effects are observed, depending on the nature of species. The dual irradiation of NO in presence of SF 6, enhances strongly some fluorescence emissions which can be six fold more intense than in presence of a sing16 ultraviolet laser irradiation. This effect gives an estimation of both the heat bath temperature and the average number of infrared photons absorbed by NO via SF6. With CF0C1,, the infrared assistance leads to a new ultraviolet fluorescence emission, equivalent to aA average tbsbrption of five infrared photons and one ultraviolet photon. This new emisssion which corresponds to the fluorescence of the state C12 (1 lai+-4*XlEg+), should be the indication of a strong enhancement of one path among the two decomposition channels, driving to the CF2 radicals formation.