Fig. 1. (a) Spin-lattice relaxation times (T₁) of , ß, and deuterium of d₅–pyridine in water as a function of pH. (b) T₁ of deuterium of d₅–pyridine in water, 0.001 M benzoic acid (C₆H₅COOH) and 0.001 M phenol (C₆H₅OH) solutions as a function of pH, and modeled T₁ in water. For both (a) and (b), the measurement error is generally <1% and approximately the same size as the symbols used).