2-DIMENSIONAL EXCHANGE SPECTROSCOPY USING PURE NQR

Exchange between positions with different resonance frequencies can be studied by two-dimensional spectroscopy originally developed for the NMR case. Cross intensity reflects changes of the resonance frequency due to different line shifts or anisotropic interactions. We now present analogous experiments carried out with pure NQR of polycrystalline samples. The specific requirements are discussed in comparison to 2D exchange NMR spectroscopy. The method has been demonstrated with chloroform and p-chlorobenzotrichloride, where the resonances of the Cl-35 nuclei were investigated. Isomeric changes taking place in these compounds reveal themselves as cross-peaks provided the right ranges of the temperature and the mixing time are chosen. The corresponding dependences were recorded and are discussed.