SPECTROSCOPY OF THE FLUOROMETHYLENE RADICALS HCF AND DCF BY 2-ENHANCED MULTIPHOTON IONIZATION SPECTROSCOPY AND BY AB-INITIO CALCULATION(1 RESONANCE)

Spectra of fluoromethylene radicals, HCF and DCF, have been observed b etween 304 and 325 nm using mass-resolved, resonance enhanced multipho ton ionization (REMPI). Singlet HCF is generated by sequential reactio ns of atomic fluorine in either methane or methyl fluoride. The spectr a arise from two-photon resonances between the ground state X ($) over tilde (1)A' and the previously unobserved E ($) over tilde (1)A' (3p) Rydberg state. The band origins lie at T-0 = 62154+/-2 cm(-1) (321.69 +/-0.01 nm) and T-0 = 62175+/-2 cm(-1) (321.58+/-0.01 nm) (2 sigma) ab ove the ground states for HCF and DCF, respectively. Vibrational resol ution and partial rotational resolution are obtained, with v(2)' = 112 8 +/- 4 cm(-1) and v(3)' = 1614 +/- 4 cm(-1) for HCF and v(1)' = 2095 +/- 5 cm(-1), v(2)' 872 +/- 3 cm(-1), and v(3)' = 1582 +/- 4 cm(-1) fo r DCF (2 sigma). Under typical experimental conditions, the strongest peak for HCF is due to the 2(0)(1)3(0)(1) resonance at 308.23+/-0.04 n m and the strongest peak for DCF is due to the 2(0)(2) resonance at 31 2.85+/-0.01 nm. The results of vibrational and rotational analyses are consistent with predictions from ab initio calculations, which also y ield the adiabatic ionization potential IPa=10.06+/-0.05 eV (2 sigma).