Abstract: A Study on the Decompositions of C_7H_5O~(2+·) Doubly Charged Ion in the Gas PhaseQiu Fenghe;Liu Shuying (Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022, China )Abstract:The unimolecular neutral losses, unimolecular charge separations,collision induced decompositions (CID ) and electron capture induced decompositions(ECID) of C_7H_5O~(2+·) doubly charged ions produced from benzyolamide in the ion source of mass spectrometer under 70 eV electron impact were studied in the present work. The decomposing products show that C_7H_5O~(2+·) mainly exists in two types of structures-intact benzene ring retaining and H migrating structures. The interferences of unimolecular decomposition products in the collision spectra (CID, ECID) were excluded by using the method of application of either a negative or a positive voltage to the collision cell.Keywords: doubly charged ions,CID,ECID