data acquisition and processing procedure

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Data acquisition and processing on a Bruker DSX spectrometer
Data acquisition of fast MAT spectra
(i)
The t1,eff = 0 slice of a 2DMAT spectrum is obtained by performing a 1D
experiment using the pulse sequence in Fig. 2 but without the two pairs of
read-out and storage pulses.
(ii)
Make a place holder for the t1 = 0 slice in the 2D pulse program, and later
incorporate the 1D t1, eff = 0 slice as the real t1 = 0 slice into both the S+ and Sdatasets (see data processing below).
(iii)
During the acquisition of 2D datasets, insert a slice of zeroes in every other t1
slice in the time domain to replicate the 2D spectra in the 1 dimension after
Fourier transform.
Data processing of fast MAT spectra (with Xwin-NMR version 3.5)
(i)
Constructing the 2D absorptive spectra
Incorporate the 1D t1,eff = 0 spectrum into S+ and S- using command “wser 1
<expno>” with the parameter Fcor in the edp window set as 0.5*0.25 = 0.125
(0.5 is for the regular first point scaling and 0.25 comes from the difference of
phase cycles in the pulse programs for 1D and 2D data acquisitions), where
<expno> is the experimental number of the 1D spectrum in the data file.
(ii)
Fourier transform S+ and S- over t1 and t2
(iii)
For generating the cosine-dataset Sc(1,2)
Sc(1,2) = (S+(1,2) + S-(1,2))/2 (2 positive diagonal ridges forming an X),
using add2d with  and  both set to 1.
(iv)
For generating the sine-dataset iSs(1,2) = (S-(1,2) - S+(1,2))/2
(a) Use wrpa to copy S+(1,  2) and S-(1,  2) to higher file numbers.
(b) In the edp window, add 90o to the constant phase correction in both
dimensions
of both copied spectra.
(c) Perform xfb on both datasets.
(d) Use wrpa to copy one of the datasets to a third file to subtract them using
add2d with = 1 and = -1.
iSs(1,2) has a positive and a negative diagonal ridge (90o phase shift in 1)
(v)
Produce Sc(1,2) + iSs(1,2) by using add2d with both  and  set to 1.
(vi)
Scale the chemical shift in 1 by a factor of 2/3.
(i)
Spectral shearing
Shear the 2D spectra first in 1 dimension by setting “1 ” = - 0.5/ (2*(STSI
of 1)/ (STSI of 2)), and execute ptilt1.
(ii)
Shear the 2D spectra in the 2 dimension by setting  = (-2/3)/((STSI of
2)/(2*(STSI of 1)), and execute ptilt.
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