Two-pulse nutation NMR
applied to a powder:
JDK1.1.8 applet




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AIM: Determination of the quadrupole coupling constant from a featureless NMR lineshape

Two-pulse nutation experiments with a short interpulse delay tau1 are more versatile than one-pulse nutation experiment: We can perform two experiments with different acquisition parameters on the same sample. The fitting of these two nutation data should provide us with the same quadrupolar coupling constant. A short tau1 avoids the formation of echoes. Three two-pulse sequences are presented:

Two-pulse sequence with a short interpulse delay tau1 for nutation NMR X-X:
{+X}-tau1-{+X}-acq(+y)

Even-X:
{+X}-tau1-{+X}-acq(+y)
{-X}-tau1-{+X}-acq(+y)

Odd-X:
{+X}-tau1-{+X}-acq(+y)
{-X}-tau1-{+X}-acq(-y)

IMAGE: Parameters for the simulation of two-pulse nutation NMR line intensity

The left part of the simulation panel indicates the physical parameters. It is preset for a typical experiment on a spin I = 3/2 in a powder. You can introduce your own values.

First, we select one of the two-pulse sequences available with the upper choice box.

Then, we select one of the two types of line intensity calculation with the lower choice box:
(1) V-T-F: p1 is variable and p2 is constant, tau1 being a parameter;
(2) F-T-V: p1 is constant and p2 is variable, tau1 being a parameter.

A constant length should be provided in the MinLength field.

MinLength: the first variable pulse-length in s

MaxLength: the last variable pulse-length in s

Step: the increment of the variable pulse-length in s

The following applet is initialized for the central-line intensity of a spin I = 3/2 in a powder excited by the X-X two-pulse sequence, where p1 = 5 s, tau1 = 10 s, and p2 increases from 0 to 10 s by 0.5 s step. The experimental line intensities are identical to the simulated ones.

 

JDK1.1.8 applet for two-pulse nutation NMR applied to a powder Applet for calculating and fitting the NMR powder line intensity of quadrupolar spin excited by the composite pulse.

Help for selecting all the simulated data of the line intensity text area in a JDK1.1.8 applet.

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