Selective excitation transfer and separated relaxation measurements of degenerate transitions in NMR spectroscopy

Abstract

A method is described by which phase coherence induced by selective excitation of a single line in a spin–spin multiplet is transferred to one or more nonirradiated transitions. Under the appropriate conditions, excitation may be transferred to individual members of groups of degenerate lines or to forbidden transitions. Detailed calculations and experimental results are given for heteronuclear AX, AX2, and AX3 systems. Selective excitation of individual transitions in degenerate groups of lines allows their transverse relaxation to be studied. Differing linewidths of various degenerate resonances in 13C‐methanol doped with chromium acetylacetonate were measured by the excitation‐transfer procedure.