PHOTOABSORPTION CROSS-SECTIONS OF CH3F, CHF3, CH3CL, AND CF2CL2 FROM 175 TO 760 A

Using synchrotron radiation as a continuum background, the absorption cross sections of CH3F, CHF3, CH3Cl, and CF 2Cl2 were measured in the 175-760 Å region using a double ionization chamber. Discrete structure was observed in CHF3 and CH3Cl and attributed to the Rydberg states converging to the known ion states. In CHF3, Rydberg states converging to the (3e) -1 and (5a1)-1 ion states with averaged vibrational frequency of 910 cm-1 were observed in the 610-640 Å region. Another Rydberg state converging to the (4a1) -1 ion state with an averaged vibrational frequency of 1080 cm -1 was also observed in the 530-540 Å region. In CH 3Cl, a Rydberg state converging to the (3a1)-1 ion state with a vibrational frequency of 2330 cm-1 was observed in the 580-620 Å region. No vibrational structure was observed in CH 3F and CF2Cl2. © 1979 American Institute of Physics.