Quadrupolar Relaxation of ²⁷Al in Aqueous Solution. I. Formulation of Relaxation Rate

Abstract

The following formula of the quadrupolar relaxation rate 1⁄T_1Q of ²⁷Al in water is derived by considering that the configuration of the water molecules in the first layer around the Al⁺⁺⁺ ion is randomly altered between the symmetries T_h and C_2v:
(Remark: Graphics omitted.)
where eq is the maximum value of the field gradient component along a principal axis at the nucleus, W₀ and W are the probabilities per unit time for the symmetry of the configuration to change from T_h to C_2v or in the reverse direction respectively, and τ_cR is the correlation time for the rotational diffusion of the hydration complex.