Size Effect in 14N Nuclear Quadrupole Resonance Spectroscopy
The influence of the size effect of the crystallites in powders on the form and width of spectral lines, on the spin-spin and spin-lattice relaxation parameters of the nuclear quadrupole resonance (NQR) of 14N nuclei in sodium nitrite was studied. It was established that a decrease of the average crystallite size produces the widening of the NQR lines and the shortening of the relaxation times in the direct method of NQR detection. It was supposed that these are the results of the spin-spin diffusion process. A multi-exponential inversion of the decays of the longitudinal and transverse components of the nuclear magnetization was used to obtain the distribution of relaxation times.
KeywordsNuclear Quadrupole Resonance Spin Diffusion Paramagnetic Impurity Relaxation Time Constant Nuclear Quadrupole Resonance Frequency
One of us (NS) thanks the Russian Foundation for Basic Research (RFBR, grant № 11-03-00124 a) for financial support. One of us (GM) was supported by NATO Science for Peace and Security Program, under Science for Peace project No. 982836.