3Q-MAS nutation pulse program for quadrupolar spins

3Q MAS two-pulse program for Bruker ASX spectrometer

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3QMAS sequence with pulse lengths p1 and p2 for nutation NMR

This is a pulse program for one-dimensional 3Q-MAS experiment whatever the quadrupolar nuclei with half-integer spin I. The echo position is tau2 = k*tau1 where:

I	3/2	5/2	7/2	9/2
k	7/9	19/12	101/45	91/36

The delay tau1 should be very short, about 10 µs. The pulse lengths p1 and p2 must be optimized in order to obtain the biggest echo amplitude. In this pulse program, the CYCLOPS procedure is missing. As a result, the image of the line in the spectrum should be observed if the spectrometer frequency differs with the Larmor frequency.

    ze
  2 d1 tlo           ; recycle duration d1
                     ; tlo set to drive HP X amplifier
    10u:c4
    p1:t:c4 ph1      ; the first-pulse duration p1
    d6:c4            ; spacing between pulses
    p2:t:c4 ph2      ; the second-pulse duration p2
    2u:c4
    d7 ph0:r         ; acquisition delay
    3u adc
    aq               ; acquisition
    1m
    rcyc=2 ph3       ; loop to 2, NS times for averaging
    wr #0
  exit

  ph0=    0
  ph1=(6) 0 1 2 3 4 5      ; p1 pulse phase
  ph2=    0                ; p2 pulse phase
  ph3=    0 2 0 2 0 2      ; receiver phase

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