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We present new and refined data for the magnetic field and temperature dependence of the proton spin-lattice relaxation rate in antiferromagnetic molecular rings as well as a new explicit scaling formula that accurately reproduces our data. The key ingredients of our formulation are (1) a reduced relaxation rate, , given by , where is the differential susceptibility, is a fitting constant, and is the proton Larmor frequency, and (2) a temperature-dependent correlation frequency which at low is given by , that we identify as a lifetime broadening of the energy levels of the exchange-coupled paramagnetic spins due to spin-acoustic phonon coupling. The main consequences are (1) has a local maximum for fixed and variable that is proportional to ; the maximum occurs at the temperature for which ; (2) for low …