The temperature dependence of the deuterium quadrupole coupling constant and the molecular rotational correlation time in liquid methanol

Abstract

Temperature dependent experimental measurements of the methanol OH proton chemical shift and the OD deuterium relaxation time for neat methanol were made over the liquid range 200–340 K. From these data values for the deuterium quadrupole coupling constant X _D and the molecular rotational correlation time τ_c, for the OD vector were obtained, X _D was found to vary from 196kHz at 200 K to 215 kHz at 340 K, while τ_c varied from 65.0 ps to 3.0 ps over the same range. Using τ_c and the liquid viscosity, the size of the supramolecular hydrogen bonded clusters present in the liquid was found to range from 0.25 nm³ at 200 K to 0.24 nm³ at 340 K.