th  - 1988 - 51st ENC Conference

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Coherent Averaging Theory Under the Condition of Strong
P, dses o4 Finite Width and Its Application
Wu Xiaoling, Zhang Shanmin , and Wu Xuewen
Department of Physics, East China Normal University,
Shanghai 200062, P.R.China
Abstract
A theory, Coherent Averaging Theory Under the Condition of
Strong Pulses of Finite Width, is presented by using perturbation
method of quantum mechanics combining with Coherent Averaging
Theory. It is proved that under the condition of strong pulse,
i.e. when the interaction coupled with RF field , ~I , is
stronger than the internal interaction among spins themselves,
~;nt , by a factor of more than six , instead of the whole ~
only the secular part in ~i~t with respect to ~1 , which
commutes with ~1 , needs to be remained during the pulse°
Compared with the method commonly used to deal with pulses
with finite width, this technique is of much more convenient
and of little lower degree of approximation in the applications.
Some applications of this method in various experiments are
discussed. Especially, equipped with this technique , we have
designed a windowless solid echo pulse sequence and a solid
state broadband composite 180 ° pulse, which are superior to
those scheme~generally utilized.
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