Transverse diffusion and interaction potential for K+drifting in Ar

Experimentally measured values of the ratio, D T /K, of the transverse diffusion coefficient to the mobility for K + ions drifting in argon gas are reported. Results were obtained with estimated accuracies of +or-3% at E/N values ranging from 10-600 Td (1 Td=10 -21 V m 2 ) and have been adjusted to 298 K. These experimental values are compared with values obtained from Monte Carlo simulations using several proposed interaction potentials as input. The comparisons suggest that none of the potentials examined is a totally accurate representation of the K + -Ar interaction potential.