Ultraviolet photoablation of p-tetrafluoroethylene: Rotational energy distributions of the CF radical and time-resolved mass spectra

Gas-phase products from the nanosecond ultraviolet excimer ablation of polytetrafluoroethylene (Teflon©) have been characterized using mass-resolved vacuum ultraviolet laser photoionization techniques. Picosecond and nanosecond vacuum ultraviolet (10.5 eV) photoionization mass spectra recorded following the ablation of polytetrafluoroethylene display a significant dependence on the ablation wavelength. Polymer fragments ranging in mass from 31 to greater than 300 amu are observed following the 193 nm ablation of the polymer, whereas using 248 and 308 nm, the mass spectra consist almost entirely of the monomer (C2F4). Rotationally resolved resonant two-photon ionization (R2PI) spectra of the CF radical, recorded following the 193 nm ablation, were used to estimate the rotational temperature of this species in the ablation plume; temperatures ranged from 500 to 800 K.