Observation of the 5p Rydberg states of sulfur difluoride radical by resonance-enhanced multiphoton ionization spectroscopy

Sulfur difluoride radicals in their ground state have been produced by a “laser-free” pulsed dc discharge of the SF6∕Ar gas mixtures in a supersonic molecular beam and detected by mass-selective resonance-enhanced multilphoton ionization (REMPI) spectroscopy in the wavelength range of 408–420nm. Analyses of the (3+1) REMPI excitation spectrum have enabled identification of three hitherto unknown Rydberg states of this radical. Following the Rydberg state labeling in our previous work [see J. Phys. Chem. A 102, 7233 (1998)], these we label the K(5p1) [ν0-0=71837cm−1, ω1′(a1symstr)=915cm−1], L(5p2) [ν0-0=72134cm−1, ω1′(a1symstr)=912cm−1], and M(5p3) [ν0-0=72336cm−1, ω1′(a1symstr)=926cm−1] Rydberg states, respectively. [Origins, relative to the lowest vibrational level of the XA11 ground state, and vibrational frequencies of the symmetric S–F stretching mode are suggested by the numbers in brackets.] Photofragmentation process of SF2+→SF++F that relates to the REMPI spectrum was discussed.