Protocol: Mqmas3qspltse2d  Sequence: mqmas3qspltse2d.c  Apptype: solidseq1d

Description: 

   Two-pulse MQMAS with a 3Q phase cycle, split t1,  a selective echo, with
   SPINAL or TPPM decoupling. 

Setup: 

   Load a calibrated data set and select the protocol Mqmas3qspltse2d. For 
   a new nucleus calibrate with Onepul and then select Mqmas3qspltse2d.  

   Select the desired decoupling method, if any, TPPM or SPINAL. The manual
   file Onepul describes calibration of decoupling. 

   Step 1: With a solid quadrupolar sample determine the maximum of the
   hard-pulse nutation curve using Onepul. The nutation curve will be 
   quite distorted and the maximum will be one-half to one-third the 
   calibrated pwX90 of a solution sample. Record aX90 and pwX90 for the 
   maximum. 

   Step 2: Redo the nutation measurement with an amplitude 20 to 30 times
   smaller. It may be necessary to reset tpwr to obtain the smaller 
   amplitude. This nutation curve will be a sinusoid. Note the 180 degree
   pulse width. For most applications set 2*pwX90 to 40 to 60 microseconds. 

   Select Mqmas3qspltse2d. Set pw1Xmqmas = pwX90 from Step 1. Set pw2Xmqmas = 
   3.0*pwX90 from Step 1. Set aXmqmas = aX90 from Step 1. 

   Set pwXechsel = 2.0*pwX90 from Step 2. Set aXechsel = aX90 from Step 2. Set
   dbXechsel = tpwr from Step 2. 

   Determine the desired acquisition time in F1 (ni-1)/sw1 that will produce
   data that is not truncated. Divide by 2 and set tXechsel to this number. Set 
   ival to the spin of the observe nucleus, 1.5, 2.5 etc. 

   Set the F1 Spectral width on the Acquisition Page equal to srate*9/16 for ival 
   = 1.5 and srate*12/31 for ival = 2.5.  Set ni = 64 and phase = 0. 

   Be sure daslp = 0 and scalesw1 = 1, if they exist. These parameters would be
   present if a sheared experimented had been run previously in the workspace. 
   Mqmas3qspltse2d does not require shearing. 

   With ni = 1 and nt = 24 or a multiple, fine adjust pw1Xmqmas and 
   pw2Xmqmas with a double array. Note that the full phase cycle is 96, 
   but 24 can give reasonable data. 

   Reset ni and run the 2D experiment. When complete, process with wft2d(1,0,0,1).
   Presently reference F1 with "rl1" using a known peak. 

Parameter Groups:

mqmasX:  Module:  no
Sequence:  mqmas3qzf2d.c
Description:  Implements two-pulse MQMAS on obs with an F1 delay d2 in
              between the pulses.
Parameters:  Sequence Page
       aXmqmas - the amplitude of the obs pulses.
       pw1Xmqmas - the first pulse of MQMAS, typically a 20 to 40-
              degree flip angle, based on the solution-state 90-degree 
              pulse.
       pw2Xmqmas - the second pulse of MQMAS, typically a 90-degree
              flip angle based on the solution-state 90-degree pulse.

echselX:  Module:  no
Sequence:  mqmas3qse2d.c
Description:  Implements a selective, square refocusing pulse with both
              amplitude and attenuation control to provide a selective echo
              in MQMAS and STMAS experiments. The amplitude change requires
              3.0 ms during the t1Xechsel delay. The attenuation is not reset.
Parameters:  Sequence Page
       aXechsel - amplitude of the obs selective echo pulse.
       dbXechsel - attenuator setting for the obs selective echo pulse.
       tXechsel - delay before the refocusing pulse requires a minimum
              value of 3.0 us for the attenuator change.
       pwXechsel - a selective 180-degree flip on obs.

Hseq:  Module:  yes
Sequence:  tancpx.c
Description: Chooses SPINAL or TPPM decoupling on the dec channel
             during acquisition
Parameters:  Sequence Page - the Hspinal and Htppm groups overlap
       Hseq - chooses the decoupling sequence, TPPM or SPINAL.
Implementation:  DSEQ dec = getdseq("H");  The router implements
             getspinal() or gettppm().
Underscore functions: _dseqon(dec); runs _tppm(); or _spinal();_
             dseqoff(dec); runs decprgoff();

Hspinal:  Module:  yes
Sequence: tancpx.c
Description:  Implements SPINAL decouping on the dec channel during
              acquisition.
Parameters:  Sequence Page
       aHspinal - amplitude of the dec channel.
       pwHspinal - approximate 180-degree flip angle on resonance.
       phHspinal - +/- small angle phase. SPINAL64 is implemented
              with phases = +/- 1.0, +/- 1.5 and +/-2.0 times
              phHspinal.
       chHspinal = 'dec' must be set (not shown).
Implementation: SPINAL dec = getspinal("H"); or DSEQ dec =
              getdseq("H");
Underscore functions: _spinal(dec); and decprgoff(); or
             _dseqon(dec); and _dseqoff(dec);

Htppm:  Module:  yes
Sequence:  tancpx.c
Description:  Implements TPPM decoupling on the dec channel during
              acquisition.
Parameters:  Sequence Page
       aHtppm - amplitude of the dec channel.
       pwHtppm - approximate 180-degree flip angle on resonance.
       phHtppm - +/- small angle phase. TPPM is implemented
              with phases = +/- 1.0 times phHtppm for alternating
              pulses.
       chHtppm = 'dec' must be set (not shown).
Implementation: TPPM dec = gettppm("H"); or DSEQ dec = getdseq("H");
Underscore functions: _tppmon(dec); and decprgoff(); or _dseqon(dec);
              and _dseqoff(dec);
