DISTORTION-FREE ELECTRON-SPIN-ECHO ENVELOPE-MODULATION SPECTRA OF DISORDERED SOLIDS OBTAINED FROM 2-DIMENSIONAL AND 3-DIMENSIONAL HYSCORE EXPERIMENTS

Simulations and experiments show that ESEEM spectra of disordered soli ds with S = 1/2 and I = 1/2 can be obtained free of dead-time artifact s and suppression effects by 2D and 3D HYSCORE experiments. The nuclea r-larmor-frequency dependence of a suppression effect related to pulse separation is demonstrated by H-1 and C-13 spectra in a 3D experiment . Extremely broad powder lines of 10 and 5 MHz width due to H-1 and na turally abundant C-13 nuclear spins, respectively, could be observed i n a coal sample, virtually free of any distortions. The interpretation of the HYSCORE correlation patterns of disordered solids is given thr ough simulations. (C) 1994 Academic Press, Inc.