Nuclear Overhauser
Effect (NOE)
Interaction between nuclear spins mediated through empty space
(#5Ă) (like ordinary
bar magnets). Important: Effect is Time-Averaged!
Give rise to dipolar relaxation (T1
and T2) and specially to cross-relaxation and the NOE effect.
the 13C signals are enhanced by a
factor
1 + h =
1 + 1/2 . g(1H)/g(13C)
~ max. of 2
Perturb
1H
spin population
affects
13C
spin population
NOE effect