Measurements of scalar spin-spin coupling in liquid HCl and HBr by N.M.R. relaxation in the rotating frame

Abstract

Measurement of the spin-lattice relaxation time in the rotating frame, T _1ρ , is shown to provide a convenient N.M.R. method for measuring the indirect nuclear spin-spin interaction between resonant nuclei and rapidly relaxing non-resonant nuclei. Conventional high resolution measurements cannot provide this information. The short relaxation times of the non-resonant spins (as short as 10^-6 s) may also be obtained where direct measurement is difficult or impossible. The advantages of this technique over the alternative method of spin echoes are discussed The scalar coupling constants and the halogen relaxation times for liquid HCl and HBr have been determined at room temperature by measuring the dependence on r.f. field strength of the proton T _{1 ρ in each liquid}