Rotational Echo Adiabatic Passage DOuble Resonance, SIMPSON 4.1.1 program

The first simulated signal amplitude in the resulting file provided by this SIMPSON program is S₀. The second signal amplitude is that of two-rotor-period REAPDOR experiment.

spinsys {
  channels   31P 27Al
  nuclei     31P 27Al
  dipole     1 2 -439  0 0 0
  quadrupole 2 2 2.8e6 0 0 0 0
}

par {
  variable index   1

  np               32
  spin_rate        10000
  proton_frequency 500e6
  start_operator   I1x
  detect_operator  I1p
  method           direct
  crystal_file     rep320
  gamma_angles     25
  sw               spin_rate/2
  variable tsw     1e6/sw
  verbose          1101
  variable rfx     50000
  variable rfy     50000
  variable t180x   0.5e6/rfx
  variable tadia   0.3e6/spin_rate
  variable tr1     0.5e6/spin_rate-t180x
  variable tr2     0.5e6/spin_rate-0.5*t180x-0.5*tadia
}

proc pulseq {} {
  global par

  reset
  delay $par(tr1)
  pulse $par(t180x) $par(rfx) x 0 x
  delay $par(tr1)
  pulse $par(t180x) $par(rfx) y 0 x
  store 1

  reset
  acq
  delay $par(tr1)
  pulse $par(t180x) $par(rfx) x 0 x
  delay $par(tr2)
  pulse $par(tadia) 0 x $par(rfy) x
  delay $par(tr2)
  pulse $par(t180x) $par(rfx) x 0 x
  delay $par(tr1)
  pulse $par(t180x) $par(rfx) y 0 x
  store 2
  acq -x

  for {set i 2} {$i < $par(np)} {incr i} {
    reset
    prop 1
    prop 2
    prop 1
    store 2
    acq -x
  }
}

proc main {} {
  global par
  
  set f [fsimpson]
  fsave $f $par(name),$par(index).fid
}

References

Otgontuul Tsetsgee, Solid-state NMR studies on precursor derived Si-B-C-N and B-C-N ceramics.