Fragmentation of the Excited Isobutane Ion Produced by Charge Transfer from the Nitrogen Molecule Ion

The radiolysis of the N2-isoC4H10 (0.0153 mol/mol of N2) mixture has been studied by using such ion scavengers as ammonia and sulfur hexafluoride. It was found that the C3H7+ ion is formed by the fragmentation of the excited isobutane ion produced by the charge transfer from the nitrogen ion. Although nitrogen is an effective quencher of the excited ion, the yield of the C3H7+ ion is constant over the pressure range from 0.66 to 130 atm. It has been concluded that the excited isobutane ion produced by the charge transfer with 5 eV excess energy decomposes very fast and that it can not be deactivated by nitrogen of 130 atm, while it has been reported by other authors that the excited isobutane ion with 1.2 eV excess energy can be deactivated below 1 atm. This difference in the characters of the excited isobutane ions can be explained by the previously-proposed mechanism of the fragmentation.