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

Abstract

Sulfur difluoride radicals in their ground state have been produced by a "laser-free" pulsed dc discharge of the SF${}_6$/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 - 420 nm. 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(5p${}_1$) [$n{u}_{0-0}$ = 71 837 cm${}^{-1}$, $omeg{a}_1^{{}^{\prime }}$(a${}_1$ sym str) = 915 cm${}^{-1}$], L(5p${}_2$) [$n{u}_{0-0}$ = 72 134 cm${}^{-1}$, $omeg{a}_1^{{}^{\prime }}$(a${}_1$ sym str) = 912 cm${}^{-1}$], and M(5p${}_3$) [$n{u}_{0-0}$ = 72 336 cm${}^{-1}$, $omeg{a}_1^{{}^{\prime }}$(a${}_1$ sym str) = 926 cm${}^{-1}$] Rydberg states, respectively. [Origins, relative to the lowest vibrational level of the X${}^1$A${}_1$ ground state, and vibrational frequencies of the symmetric S-F stretching mode are suggested by the numbers in brackets.] Photofragmentation process of SF${}_2$${}^{+}$--SF${}^{+}$ + F that relates to the REMPI spectrum was discussed.

17 pages, 1 table, 2 figures