S. Krongelb and M.W.P. Strandberg., "May 20, 1959." Reprinted from The journal of chemical physics, vol. 31, no. 5, pp. 1196-1210, November, 1959., Includes bibliographical references., Army Signal Corps Contract DA36-039-sc-78108. Dept. of the Army Task 3-99-20-001 and Project 3-99-00-000.