Protocol: Wpmlg2d  Sequence: wpmlg2d.c  Apptype: solidseq1d

Description: 

2D homonuclear correlation with PMLG in F1, a spin diffusion mixing 
period and quadrature windowed PMLG (wPMLG) for multiple-pulse 
acquisition in F2.  This sequence uses a composite preparation pulse to 
put the magnetization along -Y perpendicular to the PMLG axis of 
precession.  After F1 PMLG a tilt pulse returns precession to the XY 
plane and tilts the Y axis to Z for cosine peaks and the X axis to Z 
for sine peaks. A delay of tXmix allows mixing by spin diffusion. A 
quadrature wPMLG sequence similar to wpmlg1d.c then samples the Z axis 
magnetization in F2. PMLG and wPMLG are used with moderate-speed 
spinning (8 to 14 kHz). 
 
Additional Software

reset_wpmlg2d - This macro uses the calibrated values of pwH90 and aH90 
and srate to set up PMLG and wPMLG. The macro defaults to PMLG5 and 
wPMLG5 and sets a window for acquisition equal to two steps or 4 
microseconds, which ever is greater.  This macro is run from the 
protocol.

Setup: 

Load a calibrated data set and select the protocol Wpmlg2d.  For a new 
nucleus set the desired observe nucleus and calibrate pw90X with 
Onepul, Xx and Xmx.  Obtain a good 1D spectrum with Wpmlg1d and then 
run Wpmlg2d. 

Run the macro reset_wpmlg2d to do the calculations in the following 6 
steps.  This macro was automatically run with the protocol. 

1. Set aXprep1 = aH90.  Set pw1Xprep1 = pwX90, pw2Xprep1 = 
pwX90*54.7/90.0.
2. Set aXwpmlg = aX90.  Set pwXwpmlg = sqrt(2/3)*4.0*pwX90. The value 
of pwXwpmlg is rounded to a 12.5 ns grid and the value of aXwpmlg is 
adjusted to reflect the change. 
3. Set tauXwpmlg = (6/5)*2.0*pwXwpmlg, allowing a window of 1/6 of a 
cycle or a minimum of 4.0 us. 
4. Set sw = 1.0/tauXwpmlg. 
5. Set aXpmlg = aX90 and set pwXpmlg = sqrt(2.0/3.0)*4.0*pwX90. The 
value of pwXpmlg is rounded to a 100 ns grid and the value of aXpmlg is 
adjusted to reflect the change. 
6.  Set sw1 = 1/(10*pwXpmlg), ni = 64 and phase = 1,2. 

Set qXwpmlg = -5.  qXwpmlg = 5 is incorrect.   qXwpmlg can be reset to 
a larger value to provide wPMLGN.  The maximum value of qXwpmlg is 
determined by pwXwpmlg/qXwpmlg >= 50 ns and large values will generate 
an acquisition error. 

Set qXpmlg = -5.  qXpmlg = 5 is incorrect.   qXpmlg can be reset to a 
larger value to provide PMLGN.  The maximum value of qXpmlg is 
determined by pwXpmlg/qXpmlg >= 100 ns and large values will generate 
an acquisition error. 

Use Xx and Xmx to optimize the sample window.  For defaults set 
tauXwpmlg = 10 us set npaXwpmlg = 10.  Set r1Xwpmlg = 0.5 us, r2Xwpmlg 
= 0.5uus and r3Xwpmlg = 1.0uus.  Set rof3 = r3Xwpmlg on the Receiver 
page (important!!). 

Set scalesw = sqrt(3) and scalesw1 = sqrt(3) for an approximate default 
set of scale factors. 

If this data is to show spin diffusion mixing, set tHmix  > 0.0. 

Run the 2D data set and transform with wft2da.  If a good 1D data set 
was obtained, the 2D data should also be calibrated.   See the 
discussion of Wpmlg1d for optimization procedures.

Referencing and Scaling Wpmlg2d:

Fine-adjust the scale factor with two lines of known ppm.  A good test 
sample is n.a. glycine where the two methylene lines are 1.0 ppm apart.  
To set the F2 scale factor put a cursor on each methylene line and set 
scalesw = (ppm2- ppm1)*sfrq/delta.  To set the F1 scale factor put a 
cursor on each methylene line and set scalesw1 = (ppm2-
ppm1)*sfrq/delta1.  To reference F2 of the scaled 2D spectrum put a 
cursor on the line of interest and type rl(ppm*sfrq/scalesw).  To 
reference F1 of the scaled 2D spectrum put a cursor on the line of 
interest and type rl1(ppm*sfrq/scalesw1). 
 
Parameter Groups: 

prep1X:  Module:  no 
Sequence:  c7inadwpmlg2d.c       
Description:  Implements a composite pulse consisting of a 90-degree 
              flip followed by a smaller flip-angle to implement 
              quadrature detection about a tilted precession axis.  
              Typically followed by a windowed multiple-pulse acquisition.
Parameters:  Sequence Page
       aXprep1 - the amplitude of the obs pulses. 
       pw1Xprep1 - 90-degree flip on the obs channel. 
       pw2Xprep1 - smaller flip on the obs channel.
       phXprep1 - small-angle phase offset of the pulse. The phase must 
              be reset to zero after the pulse.

scalef1X: (processing)  Module:  no 
Sequence:  c7inadwpmlg2d.c   
Description:  Shows the F1 scale factor, scalesw1, for evolution of the 
              obs nuclei under a multiple-pulse waveform.
Parameters:  Sequence Page
       scalesw1 - the F1 scale factor. Typically scalesw1 is the inverse of 
              the mutiple-pulse scale factor.

pmlgX:  Module:  yes 
Sequence:  c7inad2dwpmlg.c      
Description:  Implements "phase modulated Lee Goldburg", PMLG, 
              homonuclear decoupling on the obs channel.
Parameters:  Sequence Page
       aXpmlg - amplitude of PMLG obs pulses.
       pwXpmlg - 360-degree flip on obs, off resonance (the length of 
              each of the two PMLG pulses).  
       nXpmlg - PMLG cycles represented in the .DEC file. 
       qXpmlg - number of phase steps in that make up pwXpmlg. A 
              negative value implements descending phases in the first pulse. 
       chXpmlg = 'dec' must be set (not shown). 
Implementation: MPSEQ pmlg = getpmlg("pmlgX",0,0.0,0.0,0,1); 
Underscore functions: _MPSEQ functions.   

scaleX: (processing)  Module:  no 
Sequence:  br24.c    
Description:  Shows the F2 scale factor, scalesw, for evolution of the 
              obs nuclei under a multiple-pulse waveform. 
Parameters:  Sequence Page
       scalesw - the F2 scale factor. Typically scalesw is the inverse 
              of the mutiple-pulse scale factor.       

wpmlgX:  Module: yes
Sequence:  wpmlg1d.c  
Description:  Implements windowed PMLG homonuclear decoupling with 
              acquisition in the window.
Parameters:  Sequence Page
       aXwpmlg - amplitude of PMLG on obs.
       pwXwpmlg - 360-degree flip on obs, off resonance (the length of 
              each of the two PMLG pulses).  
       qXwpmlg - number of phase steps that make up pwXpmlg. A negative 
              value implements descending phases in the first pulse.
       r1Xwpmlg - pre-pulse delay (similar to rof1). 
       r2Xwpmlg - post_pulse delay (similar to rd or rof2).
       r3Xwpmlg - T/R-to-rcvron delay (must equal rof3 or 2.0 us if 
              rof3 is not defined. 
       tauXwpmlg - time for one PMLG cycle including the window.
       npaXwpmlg - number of 100 ns ticks in the detection window.
       chXwpmlg = 'obs' must be set (not shown).
Implementation:  WMPA wpmlg = getwpmlg("wpmlgX");
Underscore function: _wpmlg(wpmlg,phXwpmlg);  phXwpmlg is the overall 
              phase table. 
