1. See, for example, J. Phys. (Paris) 47, C‐7 (1980);
2. I. F. Silvera, Proc. Low Temp. Conf. (LT‐16), Los Angeles, California, 1981.
3. J. T. Jones, M. H. Johnson, H. L. Mayer, S. Katz, and R. S. Wright, Aeroneutronics Systems, Inc., Publication U‐216 (1958).
4. M. W. Windsor, in Formation and Trapping of Free Radicals, edited by A. M. Bass and H. P. Broida (Academic, New York, 1960), p. 387.
5. C. E. Hecht, Physica 25, 1159 (1959).PHYSAG0031-8914