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378. DAVINS: Direct Analysis of Very Intricate NMR
Spectra
by David S. Stephenson and Gerhard Binsch, Institute of
Organic Chemistry, The University of Munich, Munich,
West Germany
DAVINS is a flexible and efficient computer program for
the fully automated analysis of high-resolution NMR
spectra.It extracts chemical shifts, indirect
coupling constants and the linewidth from an
experimental spectrum consisting of n (N < 10200)
digitized signal intensities, recorded in CW or FT
mode. The raw spectral data may be subjected to
several stages of pretreatment, including data format
conversion, pretruncation, noise calculation, baseline
flattening, smoothing and post-truncation. The
resulting preprocessed experimental spectrum, the
specification of the spin system, a set of trial
spectral parameters and a number of control constants
represent the starting point of an iterative least-
squares calculation for which no assignments of energy
levels or transitions are necessary (or indeed,
possible). The algorithm has the capability to home in
on the global minimum of the least-squares functional
in the presence of a multitude of false local minima
and is designed to do so efficiently and without the
possibility of divergence. In the majority of cases,
DAVINS will produce the correct solution from starting
trial parameters chosen randomly within specified
boundaries in a single pass; in difficult cases of
extremely tightly coupled spectra, more than one pass
through DAVINS may be required. In addition to the
standard input mode, in which n 16-bit integer data
words are read from a 9-track magnetic tape prepared by
an NMR instrument computer, three optional alternative
input routines are provided: (a) tape simulation card
input; (b) card input of hand-digitized spectra; (c)
input of line frequencies and intensities on cards.
The program outputs information about the progress of
the iteration, the final parameters, a complete error
analysis and two types of global agreement factors, and
optionally produces plots of the original, the
preprocessed experimental and the computer spectra,
either on separate sheets or as superimposed traces.
DAVINS may also be used for spectral synthesis only and
for generating output of digitized synthetic spectral
data.
NOTE: This system was developed using the CDC NOS
operating system. NOS assumes a segment loader as
opposed to the usual OVERLAY loader found in many
CDC operating systems.
FORTRAN IV EXTENDED (CDC)
Lines of Code: 3501
Recommended Citation: D. S. Stephenson and G. Binsch,
QCPE 11, 378 (1979).
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