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6.4
MEASUREMENT OF T
T
(T
in the rotating frame) is measured by using CPMAS. For the T
ρ
1
1
13
C, after transferring the excited magnetization by the CP method, the T
spin locking the magnetization. Since the CPMAS method is used, the waiting time can
be shortened in comparison with the direct-observation method.
For a peak that changes by a single exponential function, the strength M ( τ ) of magnetiza-
tion is expressed as a function of the relaxation delay time ( τ ) by the following formula.
M( τ ) = M
1.
Load the pulse sequence cpmas_spin_lock.jxp to Experiment Tool.
When measuring the T
2.
Set the Array parameters for obs_width_lock based on the estimated T
value.
Setup the array variable for performing the Torchia method in decreasing order. The
arrow buttons enable you to switch between increasing and decreasing order.
3.
Click the Set Value button.
The array parameter window closes, and the values you set are entered into
obs_spin_lock in the Experiment Tool.
4.
Click the Submit button.
The measurement starts.
Although the data processing procedure is the same as that of the inversion-recovery
method, use the following approximation formulas.
Weighted Linear Spin Lock:
Unweighted Linear Spin Lock:
Nonlinear Spin Lock:
Refer to the user's-manual "Application" for the measurement and processing of the
inversion-recovery method.
NMECAXS_V50-SLD-2
(T
ρ
1
exp(- τ / T
)
ρ
0
1
without CP, select spin_lock.jxp or spin_lock_dec.jxp.
ρ
1
6 MEASUREMENT OF RELAXATION TIME
IN THE ROTATING FRAME)
1
The weighted linear least-squares method.
The weight is deduced for the measurements hav-
ing long tau_interval.
Linear least-squares method without weight.
Nonlinear least-squares method.
measurement of
ρ
1
is measured by
ρ
1
ρ
1
6-5
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