Photoelectron asymmetry measurements for CHF3and CF4in the photon energy range 19 to 80 eV

Photoelectron asymmetry parameters ( beta ) have been measured for ionisation from the valence orbitals of the fluoromethanes CF 4 and CHF 3 . Measurements were made in the energy range from 19 to 80 eV using radiation from the SERC Daresbury SRS. The variation of beta with photoelectron energy was very close to that previously observed for Ne 2p -1 ionisation for most valence orbitals. For the 4t 2 -1 ionisation of CF 4 , however, a shape resonance was observed at an energy of 15 eV.