*** Outline ***
(A) ^{13}C CPMAS spectrum of Camphor
^{13}C CPMAS lineshapes of Camphor in a 4mm diameter rotor spinning at 5 kHz
^{13}C CPMAS spectrum of Camphor: (A) with AQ = 100 msec; (B) with AQ = 40 msec; (C) Fourier transform of SVD denoised FID of (B); (D) Fourier transform of harmonic inversion of the SVD denoised FID of (C).
Acquisition parameters:
General  
PULPROG  cp 
TD  4996 
NS  32 
DS  0 
SWH [Hz]  25000.00 
AQ [s]  0.0999900 
RG  4096 
DW [µs]  20.00 
DE [µs]  10.00 
D1 [s]  5.00000000 
NUC1  13C 
P15 [µs]  10000.00 
PL1 [dB]  5.40 
SFO1 [MHz]  100.6148134 
NUC2  1H 
P3 [µs]  9.00 
PL2 [dB]  9.40 
PL12 [dB]  14.00 
SFO2 [MHz]  400.1299619 
(B) Harmonic inversion processing procedure
+++Original data file+++
In TopSpin, process the TopSpin file C13CPcamph4BL by convdta command and
save it as C13CPcamph4BL 100.
+++Generate data with shorter AQ+++
Save TopSpin file C13CPcamph4BL 100 as a JCAMPDX file C13CPcamph4BL.dx on the Desktop of Windows.
Make a copy of the JCAMPDX file C13CPcamph4BL.dx as Copie de C13CPcamph4BL.dx on the Desktop of Windows.
Open the JCAMPDX file C13CPcamph4BL.dx with MS Blocnotes; delete the two second half parts of the FID; change the value of TD accordingly; save the JCAMPDX file as C13CPcamph4BLshort.dx on the Desktop of Windows.
Make a copy of the JCAMPDX file C13CPcamph4BLshort.dx as Copie de C13CPcamph4BLshort.dx on the Desktop of Windows.
Introduce the JCAMPDX file C13CPcamph4BLshort.dx back to TopSpin.
+++FID denoising with SVD Java applet+++
Open MS Excel, File > Open; open the JCAMPDX file C13CPcamph4BLshort.dx; select the real part and the imaginary part of the FID and paste them into SVD applet for denoising.
Save the the real part and the imaginary part of denoised FID back to the JCAMPDX file C13CPcamph4BLshort.dx with MS Excel; change the format of the cells to integer numbers; close the file by saving it as a text file.
Open the JCAMPDX file C13CPcamph4BLshort.dx as a text file with MS Blocnotes; open the JCAMPDX file Copie de C13CPcamph4BLshort.dx as a text file with MS Blocnotes; copy the FID data from C13CPcamph4BLshort.dx to Copie de C13CPcamph4BLshort.dx.
Make a copy of Copie de C13CPcamph4BLshort.dx; rename this new file as Copie de C13CPcamph4BLshortsvd.dx; then introduce it back to TopSpin.
Make a copy of Copie de C13CPcamph4BLshort.dx on the Desktop of Windows then rename it as C13CPcamph4BLshortsvd.dx.
+++Harmonic inversion applied to SVD denoised FID+++
Open MS Excel, File > Open; open C13CPcamph4BLshortsvd.dx; open a new file of OpenOffice3 Calc; select the real part and the imaginary of the FID from C13CPcamph4BLshortsvd.dx and paste them into the new OpenOffice3 Calc file; generate the complexe form of the data with the function COMPLEXE(cell; cell; "i"); then save it with filename camphecpmas.ods.
Select the complex form of the data in OpenOffice3 Calc and paste them into MS Blocnotes as a text file; save the text file with the filename mimicamphe on the Desktop of Windows; delete its filename extension if present.
Put the file mimicamphe in the folder of harminv1.3.1.
Start Cygwin:
Select and copy the data in Cygwin window; then paste them in MS Blocnotes as a text file called harminvcamphe1.txt.
Open MS Excel, File > Open; open harminvcamphe1.txt; the cell separator is comma;
With the 9 highest amplitude signals (they have low errors and small decay constants), we generate an OpenOffice3 Calc file called harminvcamphefine.ods, in which the values of decay constants are divided by ten and the number of complexe FID intensities is increased by four.
+++Generate JCAMPDX file with longer AQ++
We do not detail this last step.
Generate a new JCAMPDX file with the harmonic inversion data, called
Copie de C13CPcamph4BLharminvfine.dx,
in which some lines are modified:
TD is also changed accordingly; introduce this JCAMPDX file in TopSpin.
(C) Comments
The well known definition of the acquisition time AQ of an FID is related to the number of timedomain data points TD and the dwell time DW of the FID by:
AQ = TD*DW
From mathematical point view, the complexe points of an FID are sampled simultaneously and TD is therefore the number of complexe points of an FID.
In TopSpin, TD is the number of real sampled points plus the number of imaginary sampled points. In other words, TD is twice the number of complexe points of an FID. To maintain AQ value unchanged, DW is divided by two. As a result, the frequencies provided by harminv1.3.1 applied to TopSpin data are twice that expected, in addition to the change of signs.
NoteTab Light, a freeware text editor installable in USB key, can be used (tabulation = ^T).
tabulation in OpenOffice3:
tabulation in MS Word:
(D) Reference

Grant N. Holder, David G. Farrar, and David M. Gooden
A seniorlevel experiment in structural elucidation using 2D NMR,
Chem. Educator 4, 173176 (1999).
Abstract