THE ABSORPTION OF PULSED CO2-LASER RADIATION BY TETRAFLUOROSILANE AT VARIOUS WAVE-NUMBERS, FLUENCES, PULSE DURATIONS, TEMPERATURES, OPTICAL-PATH LENGTHS AND PRESSURES OF ABSORBING AND NONABSORBING GASES

The absorption of three lines P(30) (1037.4 cm(-1)), P(36) (1031.5 cm( -1)) and P(40) (1027.4 cm(-1)) of the pulsed CO2 laser (00(0)1-02(0)0 transition) by SiF4 was examined at various pulse energies, pulse dura tions, temperatures, optical path lengths and pressures of this compou nd and several non-absorbing gases. In addition, the low-intensity inf rared absorption spectrum of tetrafluorosilane was compared with high- intensity absorption data for all lines of the laser. The experimental dependences demonstrate nonlinear features of the absorption phenomen a originating from the high power of the incident radiation and collis ions of absorbing molecules with surroundings. These effects are inclu ded in the analytical formula, being an extended form of the Lambert-B eer law, which reasonably approximates all experimental data. The impo rtance of the results obtained for understanding general features of m ultiphoton absorption and for revealing potential applications of SiF4 as a sensitizer for the infrared region is presented in brief.