X band rapid scan EPR of samples with long electron spin relaxation times a comparison of continuous wave, pulse and rapid scan EPR

X band room temperature spectra obtained by rapid scan, continuous wave, field swept echo detected and Fourier transform electron paramagnetic resonance FTEPR were compared for three samples with long electron spin relaxation times amorphous hydrogenated silicon T1 11 amp; 956;s, T2 3.3 amp; 956;s , 0.2 N C60 solid T1 120 160 amp; 956;s, T2 2.8 amp; 956;s and neutral single substitutional nitrogen centres NS0 in diamonds T1 2300 amp; 956;s, T2 230 amp; 956;s . For each technique, experimental parameters were selected to give less than 2 broadening of the lineshape. For the same data acquisition times, the signal to noise for the rapid scan spectra was one to two orders of magnitude better than for continuous wave or field swept echo detected spectra. For amorphous hydrogenated silicon, T2 amp; 8727; amp; 8764; 10 ns is too short to perform FTEPR. For 0.2 N C60, the signal to noise ratio for rapid scan is about five times better than for FTEPR. For NS0 the signal to noise ratio is similar for rapid scan and FTEP