Mqmas Method - JEOL JNM-ECA Series User Manual

Solid measurement

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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.

7.1

OUTLINE OF MQMAS METHOD................................................................... 7-1

7.2

PRINCIPLE ........................................................................................................ 7-3

7.3

ADJUSTMENT .................................................................................................. 7-5

7.3.1

Adjustment of Power .................................................................................. 7-5

7.3.2

Adjustment of Parameters .......................................................................... 7-6

7.4

MEASUREMENT.............................................................................................. 7-8

7.5

PROCESSING.................................................................................................... 7-9

7.6

APPENDIX ...................................................................................................... 7-12

7.6.1

Shearing process....................................................................................... 7-12

7.6.2

Scaling Processing.................................................................................... 7-13

NMECAXS_V50-SLD-2

MQMAS METHOD

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Jnm-ecx series