Theory of the Dependence of Nuclear Magnetic Relaxation on the Absolute Sign of Spin—Spin Coupling Constant

It is theoretically shown that the nuclear relaxation times and the saturation parameter of each component line of two-spin spectrum depend on the sign of the spin—spin coupling constant J. Then it is suggested that the absolute sign of J can be determined through measurement of the relaxation times or saturation parameters. The experimental conditions are discussed taking two-spin systems of 13C–1H, 13C–19F, 1H–19F, and 1H–31P as examples.