MQMAS shearing with RMN(fat):
Contribution of Y. Millot

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4 - Echo file

For aluminum-27 (I = 5/2), which has a positive gyromagnetic ratio, and for 3QMAS experiment performed with the two-pulse program, the echo fecho(t1, t2) signal is related to the cosine Scos(t1, t2) and sine Ssin(t1, t2) signals by:

fecho(t1, t2) = Scos(t1, t2) + i*Ssin(t1, t2) .

To get i*Ssin(t1, t2) from Ssin(t1, t2), we must introduce the complex number i, performed in fact with a phase correction.

(1) We add a 90°-phase shift to the sin file by selecting the menu items:

Process/Phase/Parameters...

Phase correction parameter form

The Phase Correction Parameter form appears. In the text field Zero of 2nd Dimension of 2D Data area, we type 90. The other fields are zeroed.

(2) We apply the i-phase correction by selecting the menu items:

Process/Phase/Phase Correct

We obtain exp(i*Pi/2)*Ssin(t1, t2), that is, i*Ssin(t1, t2).

Intensity plot of the i-phase corrected sine file of 2D MQMAS data

Figure 1 Intensity plot of the i-phase corrected sine file of 2D MQMAS data:
Both axes of the 2D map are labeled in time units.

(3) We add the Scos(t1, t2) file to i*Ssin(t1, t2) file to build the echo file fecho(t1, t2) by selecting the menu items:

Data/Add Data...

Add files panel

A window appears, in which we add sin to cos. (The two shadowed rectangles are in fact pop-up lists of filenames, clicking on them allows us to choose files.) We save the resulting file with echo filename.

Three 2D files corresponding to the 2D echo MQMAS data appear on the desktop:

Intensity plot of the 2D echo MQMAS data

Figure 2 Intensity plot of the 2D echo MQMAS data:
Both axes of the 2D map are labeled in time units.

Solid-state NMR bibliography for:

Aluminum-27
Antimony-121/123
Arsenic-75
Barium-135/137
Beryllium-9
Bismuth-209
Boron-11
Bromine-79/81
Calcium-43
Cesium-133
Chlorine-35/37
Chromium-53
Cobalt-59
Copper-63/65
Deuterium-2
Gallium-69/71
Germanium-73
Gold-197
Hafnium-177/179
Indium-113/115
Iodine-127
Iridium-191/193
Krypton-83
Lanthanum-139
Lithium-7
Magnesium-25
Manganese-55
Mercury-201
Molybdenum-95/97
Neon-21
Nickel-61
Niobium-93
Nitrogen-14
Osmium-189
Oxygen-17
Palladium-105
Potassium-39/41
Rhenium-185/187
Rubidium-85/87
Ruthenium-99/101
Scandium-45
Sodium-23
Strontium-87
Sulfur-33
Tantalum-181
Titanium-47/49
Vanadium-51
Xenon-131
Zinc-67
Zirconium-91
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