th  - 1988 - 51st ENC Conference

A New Model for Hartmann-Hahn
Cross Relaxation in NI,iR
Wu Xiaoling , Zhang Shanmin and Wu Xuewen
Department of Physics, East China Normal University,
Shanghai 200062, P.R.China
Ab s tract
It was found out for the first time that Hartmann-I{ahn
cross relaxation between rare and abundant spins in IZ~.~ proceeds
in two stages: first, a fast energy exchange between each rare
spin S and its directly bonded I spins, and then, a much slower
one between these SI subsystems and remaining I spins. During
n
the cross relaxation, especially in the first stage, the I spin
system is not always in a quasiequilibrium state and so is not
always describable by a single temperature.
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