Experiments on selective excitation of multiple‐quantum transitions in NMR spectroscopy

摘要: Irradiating a spin system with an appropriate sequence of phase shifted pulses excites only certain orders multiple‐quantum transitions. excited. Using such sequences in preparation and detection produces large signal/noise enhancement for the spectra over nonselective excitation, as predicted from theory. In previous paper theory was presented detail. this some aspects are first outlined briefly. Experimental results then demonstrating four‐quantum, six‐quantum, A‐symmetry selection oriented benzene eight‐quantum 1‐bromobutane. A six‐quantum selective applied to nonequilibrium initial reduced density matrix proportional Ix one‐ five‐quantum spectra. The n‐quantum enhancements obtained selectivity is measured function pulse parameters. behavior that expected if one assumes limit determined by l...