Single to triple ionization of propane due to electron impact: Cross sections for the different dissociation channels

摘要

Electron impact single to triple ionization and subsequent dissociation of propane have been studied at an electron energy of 200 eV using a covariane mapping mapping technique empolying a focusing time-of-flight mass spectrometer. The dissociation channels of up to triply ionized propane have been identified and the corresponding absolute cross sections for the different dissociation channels have been obtained .Results show tat 88% of the singly ionized propane molecules are unstable and dissociated through more than 20 channels, among which 50% of the C_3H_8~+ ions dissociate into C_2H_5~+ or C_2H_4~+. All the doubly ionized propane molecules are unstable and dissociate through more than 80 channels. among whic 97% of the C_3H_8~+ ions dissociated into ion pairs. The major dissociation chanels for C_3H_8~+ are C_2H_3~++CH_3~+, H~++H~+, and C_2H_4~++CH_3~+ , while the major ionic products form the dissociation of C__3H_8~(2+) are H~+, CH_3~+ ,and C_2H_3~+