The electron spin relaxation and paramagnetic relaxation enhancement:: an application of the stochastic Liouville equation in the Langevin form

A novel theoretical approach, based on the stochastic Liouville equation (SLE) in its Langevin form, is developed to describe paramagnetic relaxation enhancement (PRE). This approach is more applicable to different dynamic models than the old slow-motion theory which was based on the SLE in the operator or Fokker-Planck form. Moreover, the SLE in the Langevin form supplies a detailed description of the electron spin relaxation in the time domain. This new approach is applied to the analysis of the T-1-NMRD profile of water protons in Ni2+(H2O)(6).