Study on the photofragment excitation spectrum of SO+2 in the range of 281-332nm

With the preparing of SO+2(21( 000)) by 3+1 multiphoton ioniz ation of the neutral SO2 molecules at 380.85nm,the photofragment exci tation (P HOFEX) spectrum in ultraviolet (UV) (281-332nm) wavelength range has been obtain ed.The PHOFEX spectrum in the UV range was assigned essentially to the SO+2(,)←SO+2(21) transitions.The transitions fr om 21(000) to the bend vibration levels of SO+2() were suggested,new harmon ic bend vibrational frequency ν2=241.78±0.92cm-1 and the anharmonicity constant X22=-1.71±0.01cm-1 for SO+2() was deduced.By using th e SO+ PHOFEX spectra in UV and in visible range (562-664nm), the symm etry of ,, states of SO+2 and the predissociation mechanism of SO+2(,,) were determined,that is,(i)the symmetry of ,, states of SO+2 s hould be 2 B22121( ii) around ,, states there should be two r epulsive states of symmetry α22 and β22converging to the dissociation limit of SO+(X2П)+O(3Pg),(iii)the couplings betw een 2B1 and α2A2 and betwee n 2 B2 and β2Β2,lead to the dissociation to S O+(X2П)+O(3g).