Bloch-Siegert phase shift

Bloch-Siegert Phase Shift Compensated PIPs 36... 

BLOCH-SIEGERT PHASE SHIFT COMPENSATED PIPS 5.1. Bloch-Siegert phase shift... 

Bloch-Siegert phase shift is usually introduced in homonuclear nuclear decoupling with an inversion pulse that is far off-resonance to the spins in precession. To minimize the disturbance, the strength of the inversion pulse... 

Phase incremented double adiabatic decoupling for compensation of the Bloch-Siegert frequency shift... 

As with any other homonuclear decoupling, the transverse magnetization of the 13C , for example in the evolution time, is perturbed by the decoupling pulse, resulting in an additional precession virtually around the z axis. Since the adiabatic decoupling is applied during the entire evolution time of the 13C , a non-linear frequency shift rather than a phase shift appears in the spectrum. This is termed the Bloch-Siegert (frequency) shift in the NMR literature in honour of their discovery of the phenomenon. 

It should be noted that in both the TRAPDOR and REAPDOR experiments, the rf field on the dephasing quadrupolar nucleus remains on for a considerable time, which can result in a Bloch-Siegert shift (Bloch and Siegert 1940) appearing as a misset in the zero-order phasing of the reduced echo compared to the full echo spectrum. 

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