張瑞香余健治2014-10-272014-10-271977-06-??http://rportal.lib.ntnu.edu.tw/handle/20.500.12235/17165A stable free radical which can be identified as ‧CH2NH3+ has been observed in γ-ray irradiated crystals of methylammonium aluminum Alum (MASD). The isotropic components of the hydrogen and nitrogen hyperfine splittings were mea-sured and these constants were used to calculate the s -orbital part of the spin density of the unpaired electron in the free radical.