Basic Concepts
Refocussing

Refocussing

The concept of refocussing chemical shift is common to many pulse sequences. This task is performed by inserting a 180 degree pulse in the middle of an evolution time. The effect of the refocussing pulse on the coupling (homo and heteronuclear) is different depending if a 180 degree pulse is applied or not to the two interacting nucle. The above animation review different aspect of the refocussing. Included in the animation are Bird and Tango pulse.