Electronic Band Systems of SF↓(2) Radicals Observed by Resonance-Enhanced Multiphoton Ionization

摘要

A pulsed dc electric discharge in a pulsed supersonic beam has been used as an efficient source of producing radicals. The (2+1) REMPI spectra of the SF↓(2) radicals were investigated between 245 and 365 nm (54945-81630 cm↑(-1)). Eight electronic band systems have been observed in this range. One series with quantum defect 6 = 1.961(6) is comprised of the B ↑(1)B↓(1)(4s) and J ↑(1)B↓(1)(5s) Rydberg states which have origins at v↓(0-0) = 54470 and 68951 cm↑(-1), respectively. Vibrational analyses of these Rydberg states showed that in the↑(1)B↓(1)(4s) state ω↓(1)↑(')(a↓(1) sym str) = 981(23) cm↑(-1) and in the J ↑(1)B↓(1)(5s) state ω↓(1)↑(')(a↓(1) sym str) = 942(3) cm↑-1). A second Rydberg series E (4p) with quantum defect δ = 1.61 is characterized with the spectroscopic values v↓(0-0) = 62025 cm↑(-1), ω↓(1)↑(')(a↓(1) s ym str) = 941(27) cm↑(-1), and ω↓(2)↑(')(a↓(1), bend) = 413(12) cm↑(-1). Incompletely rotational analysis revealed that the F electronic state with V0-o = 63812 cm↑(-1), ω↓(1)↑(')(a↓(1) sym str) = 966(6) cm↑(-1), and ω↓(2)↑(')(a↓(1), bend) = 417(23) cm↑(-1) merges with the vibrational progression of the E (4p) state. The F state might be a 4p Rydberg state of another hybrid symmetry with the quantum defect c5 = 1.50. A third Rydberg series is comprised of the G (3d) (v↓(0-0) = 68378 cm↑(-1), ω↓(1)↑(') = 939(12) cm↑(-1), 6 = 0.086), the H (3d) (v↓(0-0) = 68571 cm↑(-1), ω↓(1)↑(') = 936(4) cm↑(-1), δ = 0.064), and the I (3d) (v↓(0-0) = 68847 cm↑(-1), ω↓(1)↑(') = 933(4) cm↑(-1), δ = 0.032). In addition, two valence states labeled as the B↑(') state (38623 cm↑(-1)) and C state (56219-61278 cm↑(-1)) were also observed. A fit of the Rydberg formula to the ns(↑(1)B↓(1) (n = 4,5) origins found the adiabatic ionization potential of SF↓(2) radicals to be IP↓(a) = 10.021(1) eV.