Photoenhanced electron attachment of vinylchloride and trifluoroethylene at 193 nm

We show that the electron attachment properties of a gas mixture of helium containing vinylchloride or trifluoroethylene can be altered from nonattaching to strongly attaching by irradiation with a low-energy laser pulse at 193 nm. These molecules are photodissociated producing vibrationally excited HCl or HF and other fragments that strongly attach low-energy electrons.