6 MEASUREMENT OF RELAXATION TIME
6-6
NMECAXS_V50-SLD-2
6.5 RELAXATION TIME MEASUREMENT OF
1
H BY INDI-
RECT OBSERVATION USING CP METHOD
In the solid-state NMR, when measuring the relaxation time of the
1
H nucleus, indirect
observation can be performed using the CP method. When the spectrum of
1
H is broad
and cannot be observed directly, or when the sample consists of many elements, this in-
direct observation method is effective. The principle and measurement procedures are the
same as that of the measuring method by direct observation.
■
Relaxation time measurement by inversion-recovery method
When the relaxation time of
1
H is measured by using the inversion-recovery method with
CPMAS, the following pulse sequence is used.
inversion_recovery_1h_cpmas.jxp
In the usual inversion-recovery method using CPMAS, the inversion-recovery method is
performed after the magnetization transfer. However, in the relaxation-time measurement
of
1
H, the magnetization transfer is performed after the inversion-recovery method.
■
Measurement of
T
1
ρ
The following pulse sequence is used for measuring the T
1
ρ
(T
1
in the rotating frame) of
1
H by the CPMAS method.
cpmas_spin_lock_1h.jxp
Although the spin lock is applied after magnetization transfer in the usual T
1
ρ
measure-
ment, the magnetization transfer is performed after the spin lock in the T
1
ρ
measurement
of the
1
H nucleus.
