Structure and Dynamics of (CH_3)_3N-CH_2 Radical Generated in #gamma#-Irradiated Al-offretite

摘要

An EPR study was carried out to investigate structure and motional dynamics of the [(CH_3)_3N-CH_2] radical formed in a #gamma#-irradiated Al-offretite. The temperature dependent EPR spectra were observed in a temperature range between 110 K and 300 K and were interpreted in terms of a rotation of the methyl hydrogens around the N-CH_3 bond. Assuming three site jump model, the EPR line shapes were successfully simulated using jump rate as a variable parameter. The rate was found to increase from 7.0X10~6 Hz (140 K) to 5.2X10~8 Hz (300 K) with temperature, and an activation energy of 8.1 kJ mol~-1 was evaluated for the mthyl group rotation.