Symmetrical composite pulse sequences for NMR population inversion. II. Compensation of resonance offset

Abstract

A five-pulse sequence R x(90°) R y(200°) R −y(80°) R y(200°) R x(90°) is suggested for population inversion of all resonances in a spectrum whose width may be nearly twice as large as the radiofrequency field strength. The population inversion is very fast and is easier to implement than comparable methods such as adiabatic rapid passage. The composite pulse is derived from previous three-pulse sequences with the aid of mathematical and geometrical arguments, and computer simulation. Experimental results are shown and are compared with computer simulations, and with results for previous composite pulses.