A new method for the determination of the dynamic isotope effect and the deuterium quadrupole coupling constant in liquids

Using a self-consistent NMR method, it is now possible to determine both the deuterium quadrupole coupling constant as well as the rotational dynamic isotope effect in liquids. We successfully tested the method on benzene for temperatures between 280 K and 293 K. The average value of 185(3) kHz for the coupling constant is compared with measurements in solid state and gas phase. As might be expected for liquids without hydrogen bonds, no difference can be detected. A rotational dynamic isotope effect of 6(3)% is observed. This value is significantly smaller than 20(5)%, the only other result reported in the literature. The results are corrected for the influence of vibrational motion. Copyright 1998 Academic Press.