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Negative‐ion mass spectrometric study of ion‐pair formation in the vacuum ultraviolet. VII—SO 2 → O − + SO + , O − + S + + O
Author(s) -
Mitsuke Koichiro,
Suzuki Shinzo,
Imamura Takashi,
Koyano Inosuke
Publication year - 1993
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210280412
Subject(s) - photoexcitation , ion , photodissociation , chemistry , mass spectrometry , atomic physics , rydberg formula , ultraviolet , range (aeronautics) , analytical chemistry (journal) , photon energy , photon , photochemistry , physics , materials science , excited state , ionization , optics , organic chemistry , chromatography , composite material
Abstract Ion‐pair formation from photoexcitation of SO 2 was studied by negative‐ion mass spectrometry using synchrotron radiation in the 15–35 eV photon energy range. Negative ions O − from SO 2 were observed. The appearance energy in the photodissociation efficiency curve for O − is in good agreement with the thermochemical threshold of 14.49 eV for the formation of O − ( 2 P u ) + SO + (X̃ 2 Π). Three vibrational progressions in the efficiency curves are assigned as resulting from predissociation of the s‐type Rydberg states converging to SO 2 + (D̃ 2 A 1 ). The O − efficiency rises markedly at wavelengths of 622 and 570 Å. These onsets are attributed to formation of triplets of fragments: O − ( 2 P u ) + S + ( 4 S u ) + O( 3 P g ) and O − ( 2 P u ) + S + ( 2 D u ) + O( 3 P g ).