The direct observation of a highly mobile positive ion in nanosecond pulse irradiated liquid cyclohexane

The electrical conductivity induced by pulse irradiation of liquid cyclohexane has been studied by means of microwave absorption. The conductivity in pure cyclohexane, due principally to the excess electron, is reduced to less than 10% of the initial value on addition of 5 × 10^?4 M of the electron scavenger SF₆. The conductivity remaining after addition of SF₆ is however more than an order of magnitude larger than expected for massive ions in cyclohexane and, since it is almost completely removed by the addition of 4 × 10^?3 M of the positive ion scavenger NH₃, is attributed mainly to the high mobility of the positive hole in this liquid. The ratio of the electron to hole mobility is determined to be 15. The mean lifetime of the hole under the present conditions is 86 ns. The rate constant for reaction of the hole with NH₃ is determined to be 1.8 × 10¹¹ M^?1 s^?1. From the conductivity remaining after removal of both the electron and the hole the sum of the mobilities of the resulting molecular ions is determined to be 8.4 × 10^?4 cm² V^?1 s^?1.