High resolution FTIR and diode laser spectroscopy of trifluoromethylacetylene and tetrafluoromethane in a supersonic jet expansion

We report high resolution infrared spectra in the CF stretching fundamental ranges of trifluoromethylacetylene (CF3−C≡C-H, 3,3,3-trifluoropropyne) and tetrafluoromethane (CF4, R14, PCF-14, Halocarbon14). For experiments a diode laser setup combined with supersonic jet expansion is described, achieving approximate rotational temperatures between 5 10 K for CF4, using pulsed slit nozzle providing effective optical path lengths 3 to 4 cm single pass. Slightly higher (near 30 K) CF3CCH greatly simplify rotational-vibrational structure this molecule, which we also Fourier transform (FTIR) at room temperature nearly Doppler limited (instrumental bandwidth 0.001 cm−1) Zürich prototype spectrometer ZP 2001 (Bruker IFS125). The analysis CF3-symmetric (A1) ν3 provides accurate spectroscopic parameters ground excited vibrational states band centre ν~3 = (1253.4985 ± 0.0015) cm−1 from least squares adjustment more than 1100 line data root mean square deviation drms less 0.0003 cm−1. low degenerate (F2) CF4 show very simple clusters can be analysed an term formula. are essentially instrument smallest width near 0.002 assignment P(1) 1283.33693 (about terms energy (v3 1, J 0, F1− (3F2+)) level (1283.7193 0.002) Also isolated R(0) 1283.48420 well defined J' A2+ (5A1+)) level. results discussed relation HITRAN tables, earlier FTIR data, new frequency comb based CF4. discuss possible studies nuclear spin symmetry conservation lower would required, concept study parity violation by crossing experiment molecular beam spectroscopy.