Test of a numerical optimization algorithm for obtaining cross sections for multiple collision processes from electron swarm data

A numerical optimization technique is used to obtain low-energy momentum transfer, j=0 to 2 rotational and v=0 to 1 vibrational, cross sections from measured electron swarm data for parahydrogen. The downhill simplex algorithm is used to find cross sections that represent the best numerical fit to the measured electron drift velocity and characteristic energy over a range of E/N. These results, which are in excellent agreement with published cross sections derived using traditional swarm analysis techniques, demonstrate the feasibility of using automated computational algorithms for swarm analysis involving the estimation of multiple cross sections.