VUV electronic state spectroscopy of 1,1-difluoroethene and difluorochloromethane by high resolution synchrotron radiation.

High resolution VUV photoabsorption spectra of 1,1-difluoroethene (C(2)H(2)F(2)) and difluorochloromethane (CF(2)HCl) are reported in the wavelength range 115-200 nm (10.8-6.2 eV). New photoabsorption features are observed in C(2)H(2)F(2) and some Rydberg and vibrational assignments are proposed for the first time. Evidence for a weak vibrational pattern in CF(2)HCl is discussed here for the first time. Absolute cross section values have been obtained allowing photolysis lifetimes to be derived in the Earth's troposphere and stratosphere.