Multiple Proton Magnetic Resonance Relaxation in a Number of Molecular Liquids

Abstract

Experimental results are given for the proton spin-lattice relaxation times; T1 at 47.5 Mc/s for liquid ethyl benzene, bromobenzene, chlorobenzene, fluorobenzine, benzene, aniline, paraxylene, mesitylene and methyl alcohol over the whole liquid range including some supercooling. Where more than one chemical type of proton is present the distinct T1 values have been measured by a method described earlier this year by Powles and Neale. In ethyl benzene the ring proton T1 has a minimum but the ethyl proton T1 does not (as reported by Powles and Neale for toluene), thus emphasizing the difference in their nature. Motional correlation frequencies are deduced from the T1 values. In ethyl benzene and aniline the substituent correlation frequency agrees with the dielectric correlation frequency. Methyl alcohol is different. The predicted ring proton correlation frequencies are lower to an extent which depends on the particular molecule and on the interpretation adopted. The results are related to shear viscosity data. T1 T should not depend on temperature but does, in a way depending on the molecule and on the individual value of T1. Thus the introduction of the viscosity in this way is not very helpful.