ESR of UV Irradiated Oxalic Acid Single Crystal

Abstract

The UV irradiated samples of vacuumed powder and single crystal of oxalic acid two hydrate (C<inf>2</inf>H<inf>2</inf>O<inf>4</inf>.2H<inf>2</inf>O) have been investigated by the ESR method. The spectra of these single crystal and unvacuumed powder have been attributed to radical, but the peaks belonging to this radical in the UV irradiated powder sample have not been observed on the spectrum after having been vacuumed. After A and g tensor values of this radical have been calculated, it was observed to be anisotropic. The g factor was found to be only very slightly anisotropic with an average value of 2.00449. The hyperfine interaction tensors of the unpaired electron with the two H nuclei have been determined. At low temperature, the considerable change in the spectrum has not been observed.