## Example 1 of MQMAS simulation

The example deals with the **central-transition echo
amplitude** of a **spin I = 3/2** in a powder sample rotating
at the magic angle with a **rotor speed of 10 kHz**.

The strength of the **RF magnetic field is 100 kHz**.

The values of the two quadrupole parameters are **1000 kHz
for the quadrupole coupling constant QCC** and **0 for
the asymmetry parameter eta**.

The simulated experiment associated with the MQMAS
sequence is **A(p1)B()**, where the first-pulse length
**p1 increases from 0 to 20 µs by 0.5 µs step**; the
second-pulse length **p2 is 1.5 µs**.

The pulse length to pulse increment ratios are integers.

The number of integration steps for alpha and for beta
Euler angles are **MaxAlpha = 20**, that for gamma Euler angle
is **MaxGamma = 10**.

The first pulse excites **the -3-quantum coherence only**.

The sign of the central-transition echo amplitude **does not change**
for a long range of the first-pulse length p1. This curve is identical
to that obtained in Example 1 of two-pulse MAS simulation, but with higher
amplitude.