3Q MAS two-pulse program for Bruker MSL spectrometer
Contributor: J. Virlet

This is a pulse program for 2-dimensional 3Q-MAS experiment whatever the quadrupolar nuclei with half-integer spin I. The echo position is tau2 = k*tau1 where:

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.

Pulse program

    ; VIRLETC.PC
    ; premiere partie de sequence 3Q commune 3Q+ et 3Q-
    PROT ALL
            LOOP C1 TIMES
            10U     ++PLS1
            10U     ++PLS2
            END LOOP

    START,  D1      [F1 @PLS1 RGATE]  : transfer to T33s Iy14
            D4      [         RGATE]
            D2      [F1 @PLS2 RGATE]  ; transfer back to Iy23
            D3      [STA RGATE]
            D0      [++PLS1 ++PLS2]
    GOTO START

    BEGIN LISTS
    PLS1,   K0 (0/100)    (0/)   (30/)   (30/)
                 (60/)   (60/)   (90/)   (90/)
                (120/)  (120/)  (150/)  (150/)
                (180/)  (180/)  (210/)  (210/)
                (240/)  (240/)  (270/)  (270/)
                (300/)  (300/)  (330/)  (330/)
    PLS2,   K0 (0/100)  (180/)   (90/)  (270/)
    ;Liste de phases pour 3Q+
    RLS,    X X -Y -Y -X -X Y Y
    END LISTS
  

Acquisition AU program

    ;VIRLET.AUM
    ;AU program to use in conjunction with the VIRLETC.PC sequence
    ;to generate 2D MQ DAS Hypercomplex data sets.
    ;Interleaved simultaneous acquisition in the t1 dimension.
    ;SET NE TO NUMBER OF PAIR OF T1 POINTS, AND NF TO 2*NE

        D4 = 4U

    1   C1 = 0      ;Set C1=2 for cosine type echo.
        ZE
        GO
        WR #1
        IF #1

        C1 = 1      ;Set C1=1 for sine type echo.
        ZE
        GO
        WR #1
        IF #1

        I4          ;Increment t1=D4 and recycle

        IN = 1

        EXIT