Abstract: In the present paper,the dynamic isotope effect of ¹⁴N relaxation of DMF/H₂O(D₂O) system is reportcd.The ¹⁴N rclaxation times of DMF in DMF/H₂O and DMF/D₂O systems have been measured through all composition range (mole fraction of DMF from 0 to 1).The solvent isotope effect on relaxation and the factors affecting the quadrupole relaxation are discussed.The results suggest that in the given system there is a close relationship between the ¹⁴N relaxation and the kinetics of solvent water.Under infinite dilutions,the kinetics of the solute molcculcs are controlled complctely by the solvent molecules.

Key words: ¹⁴N relaxation, Isotope effect, DMF