THE ULTRAVIOLET EFFECT ON THE ALANINE RADICALS AND ITS RESOLUTION ENHANCED ELECTRON-PARAMAGNETIC-RESONANCE POWDER PATTERN

This study reports the electron paramagnetic resonance powder-line str ucture of gamma-ray-induced DL-alanine radicals, and its changes when these radicals are exposed to ultraviolet (UV) light. Deconvolution re sults show that the resolution enhanced powder pattern of UV-free and UV-exposed alanine radicals may consist of five pairs of superimposed quintets on quartets, and a doublet whose line intensity is proportion al to that of the quarters. From the analysis of such. resolution enha nced powder patterns, one may expect that the four alanine radicals pe r unit cell could always be magnetically grouped by pairs, irrespectiv e of any crystalline axis orientation with respect to the magnetic fie ld. Additionally, as the gamma-ray-irradiated powdered DL-alanine is U V-exposed, a line broadening effect concomitant to the signal loss of the strongest resonance line is observed. These spectral UV-time-depen dent variations, as well as the near constancy of the total spectral a rea, might reject the coexistence of two alanine radical populations, but may suggest a recombination process among the alanine radicals of a single radical species population that is very stable at atmospheric conditions but UV-triggered.