Program 'Spin' solves the Schrödinger equation of the given spinsystem of up to 8 protons. The Hamilton matrix is exactly composed and then diagonalized producing the spin eigenvalues (from which > NMR transition frequencies) and eigenvectors (> intensities of the allowed transitions within the spin system). With 'NMRplot' the spectrum is plotted by overlaying the calculated 'stick'plot with a Lorentzian line shape. The chemical shifts for the envisaged frequency (or magnetic field strength) of the simulated NMR spectrometer and the spinspin coupling constants are given as input. The listing of the Pascal source program explains all the steps of the calculation in detail The result is so good that the program is often used to simulate observed spectra in order to retrieve chemical shifts and spin coupling constants. This can be automatized with the 'NMRfit' program which starts with a trial set of these constants and then varies them in a 'least squares fit' between a measured and a simulated spectrum until the sum of the errorsquares reaches a minimum.
For an interactive tutorial about FourierTransform NMR and
all its more subtle features, see suite of
MathCad programs by Scott E. Van Bramer, Widener University, Chester, PA 19013.
