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A simplex optimized INDO calculation of 13C chemical shifts in hydrocarbons

✍ Scribed by D. B. Chesnut; F. W. Whitehurst

Publisher: John Wiley and Sons
Year: 1980
Tongue: English
Weight: 803 KB
Volume: 1
Category: Article
ISSN: 0192-8651
DOI: 10.1002/jcc.540010105

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✦ Synopsis

Abstract

The variable‐size simplex optimization method is used to reparametrize the I + A and β parameters of an INDO approximation to the perturbed Hartree–Fock calculation of ^13^C chemical shifts in hydrocarbons. The absolute shifts for 39 nuclei in a set of molecules containing up to four carbons are reproduced within a standard error of 9.9 ppm for an unconstrained optimization and to a standard error of 10.0 ppm for an optimization constrained to yield gross atomic charges in agreement with double‐zeta ab initio calculations.

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