7
MQMAS METHOD
Nuclei having a half-integer spin have quadrupolar interactions that do not exist in nu-
clei with a nuclear spin 1/2. Therefore, MAS by itself usually cannot obtain a high-
resolution spectrum, and the MAS data cannot be used for the analysis of a compli-
cated compound. In order to measure a nucleus having a half-integer spin, it is neces-
sary to perform a measurement that removes this quadrupolar interaction.
The DOR (Double Rotation) method, the DAS (Dynamic Angle Spinning) method, and
the MQ (Multiple Quantum)-MAS method are known as measuring methods that re-
move quadrupolar interactions. However, since the DOR method and the DAS method
need a special probe, they are not general techniques.
Chapter 7 explains the MQMAS method that is the most generally used method for the
measurement of a nucleus with a half-integer spin.
OUTLINE OF MQMAS METHOD................................................................... 7-1
NMECAXS_V50-SLD-2
