PHOFEX Continuum Spectra of SO2 + in Range (563 ～660 nm)

The photodissociation process of SO2+ molecular ions has been investigated by measuring the photofragment SO+excitation (PHOFEX) spectrum in visible (563~660 nm) wavelength range under the condition of supersonic molecular beam. The SO2+molecular ion were prepared purely by 3+1 multiphoton ionization of the neutral SO2 molecules at 380.85 nm. The SO+ PHOFEX spectrum in 563~660 nm range is continuum without any clear structure and the dissociation efficiency producing SO+ decreases with the laser wavelengths toward to red direction. These facts means that there should be a repulsive state ofα2A2around SO2+ (E, D , C). The 1+1 photodissociation mechanism of producing SO+ is suggested. Firstly, SO2+(~X2A1) ions is excited into the energy range with high dense levels of the middle state~B2B2, then SO2+(~B2B2) ions is excited into theα2A2repulsivestate by absorbing another photon, and finally dissociates to SO+(X2Π) +O(3Pg) directly .