216 (327) BRUKER BIOSPIN User Manual Version 002
Basic MQ-MAS
site for a CT selective pulse is most likely to be fulfilled. For the calibration of this
pulse a power level around 30 dB with 500 W and 1 kW amplifiers and around 20
dB with 300 W amplifiers should be expected. The pulse program zg (which uses
p1 and pl1) or zgsel.av (which uses P3 and PL21) can be used.
Figure 17.3. shows a comparison of a spectrum excited by a short non-selective
pulse with a spectrum that has been obtained by a weak selective pulse. Note that
in the latter the spinning sidebands from the satellite transition are no longer visi
-
ble which is used as an indication that it is not excited.
Table 17.1. Some Useful Samples for Half-integer Spin Nuclei
Nucleus Spin
Spectrometer
Frequency
*1)
d1 [s]
*3)
Sample Comments
17
O 5/2 67.78 2 NaPO
3
> 10% enriched
11
B 3/2 160.42 >5 H
3
BO
3
23
Na 3/2 132.29 10 Na
2
HPO
4
*2)
27
Al 5/2 130.32 5 YAG
27
Al 5/2 130.32 0.5 Al
2
O
3
27
Al 5/2 130.32 0.5 VPI-5
27
Al 5/2 130.32 0.5 AlPO
4
-14
11
B 3/2 160.46 5 H
3
BO
3
87
Rb 3/2 163.61 0.5 RbNO
3
93
Nb 9/2 122.25 1 LiNbO
3
*1)
In MHz at 11.7 T (i.e. 500.13 MHz proton frequency)
*2)
Alternatively Na
2
HPO
4
* 2H
2
O can be used. For anhydrous Na
2
HPO
4
the sample should be dried at 70° C for a
couple of hours before packing the rotor in order to eliminate crystal water completely
*3)
Recycle delays at 11.7 T, longer delays may be required at higher fields
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