High-pressure investigations of positive ion-molecule reactions in a mixture of H2S and CH4

The positive ion-molecule reactions in the mixtures of hydrogen sulfide and methane have been examined by means of quadrupole mass spectrometer with the high-pressure ion source. The concentration of hydrogen sulfide in mixtures ranged from 10% to 90% with 10% increment. For each mixture major bimolecular ion-molecule reactions have been identified in the total pressure range from 0.7 to 33.3 Pa. The electron energy for all measurements was fixed at 300 eV and the repeller potential was maintained at 5 V. Relative intensities of ion currents for the observed ions C+, CH+, CH2+, CH3+, CH4+, CH5+, C2H3+, C2H4+, C2H5+, S+, HS+, H2S+, H3S+, (H3S+)-S-34, CHS+, CH3S+, S-2(+), HS2+ and H2S2+ were determined as a function of total gas pressure inside the ion source collision chamber, repeller potential and concentration of methane in the mixture. (C) 2009 Published by Elsevier Ltd.