Search

A detailed comparative analysis of several possible input circuits for observing NMR free precession signals is given. Special attention is paid to the case of signals having short decay time constants. Here the presence of a large initial ringing transient makes it necessary to consider possible modifications in the design of the receiver system. The analysis indicates that an untuned transformer coupled input circuit is potentially superior to the traditional parallel resonant circuit in this case.

Experimental data are presented on proton spin relaxation in aqueous Cr(III) solutions of varying acidity, at 0°C. A theoretical analysis is given on the assumption that the dominant proton‐exchange mechanism for the hexaquo complex is the reaction Cr(H2O)63++H2O⇌Cr(H2O)5OH2++H3O+.