Multidimensional NQR Spectroscopy — A New Tool in Studies of Molecular Dynamics

Two-dimensional exchange 35Cl nuclear quadrupole resonance spec-troscopy for studies of the CCl3-group reorientation processes in hexa-chloroethane and chloral hydrate has been applied. Experimental results were interpreted on the basis of the 2D exchange nuclear quadrupole reso-nance theory, which takes into account the off-resonance irradiation. It has been demonstrated that 2D nuclear quadrupole resonance exchange spec-troscopy is appropriate for quantitative studies of exchange processes in molecular crystals containing quadrupolar nuclei. The method is of par-ticular value for the detection of exchange networks in systems with many sites. Thus, detailed information on the exchange pathways within a net-work of structural isomers can be deduced and a proper assignment of the nuclear quadrupole resonance lines can be made. Temperature dependence of the exchange rate was studied. The mixing dynamics by exchange and the expected cross-peak intensities have been derived. PACS numbers: 76.60.Gv, 82.56.Fk, 82.20.Pm 1