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365. DNMR5:Iterative Nuclear Magnetic Resonance
Program for Unsaturated Exchange-Broadened Bandshapes
by David S. Stephenson and Gerhard Binsch, Institute of Organic Chemistry, University of Munich, Munich, FRG DNMR5 is the iterative version of DNMR3 (QCPE 165). It uses an improved and simplified DNMR3 as a subroutine. Up to 16 parameters (chemical shifts, coupling constants, populations, effective transverse relaxation times, exchange rate constants, 2 baseline parameters and the spectral origin) may simultaneously be optimized by the least-squares fitting of a theoretical bandshape to experimental digitized CW NMR signal intensities. The optimization is constrained by the total experimental bandshape integral corrected for baseline increment and baseline tilt. The iterative minimization algorithm is based on a judicious interpolation between the gradient and Gauss-Newton parameter correction vectors with respect to direction as well as length. In standard operation, the experimental spectrum is to be supplied as 10200 16-bit integer data words on a 9-track magnetic tape prepared by a modern NMR spectrometer system. For users lacking the capability to prepare such a tape, two alternative optional input routines are provided. The raw band- shape data are smoothed and truncated prior to the iterative calculation. The program outputs information about the progress of the iteration, an error analysis of the final parameters and an agreement factor based on a calculated RMS noise figure, and optionally produces plots of the original spectrum, of the smoothed and truncated spectrum, and of the computed spectrum, either on separate sheets or as superimposed traces. QCPE does not supply the plotting routines. These will be identified as UNDEFINED EXTERNAL REFERENCES when execution is attempted. FORTRAN Extended (CDC Cyber 175) Lines of Code: 3651 Recommended Citation: D. S. Stephenson and G. Binsch, QCPE 11, 365 (1978). |