SINGLEPHOTON AND MULTIPHOTON ABSORPTION OF CARBON-DIOXIDE LASER LINESBY SO2 AND CO2 MOLECULES

We have used 60 rovibrational lines of a Lumonics TEA CO2 laser to rec ord the spectra of coincidence of SO2 IR absorption with CO2 laser emi ssion. We extended the same type of investigation to CO2 molecules and observed an absorption at practically all the rovibrational lines of the laser. We have also recorded the increase of absorption with press ure of the studied molecule and with its temperature. Our work reveals very accurately the fine structure of these absorptions that shows a clear discreteness in the intensities of the lines. Some implication o f this discreteness in multiphoton absorption is also presented, throu gh data that indicate very strong vibrational coupling between ground and excited electronic states of SO2.