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Chemical shift driven geometry optimization

✍ Scribed by Raiker Witter; Wolfram Prie; Ulrich Sternberg

Book ID
102304235
Publisher
John Wiley and Sons
Year
2001
Tongue
English
Weight
169 KB
Volume
23
Category
Article
ISSN
0192-8651

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✦ Synopsis

Abstract

A new method for refinement of 3D molecular structures by geometry optimization is presented. Prerequisites are a force field and a very fast procedure for the calculation of chemical shifts in every step of optimization. To the energy, provided by the force field (COSMOS force field), a pseudoenergy, depending on the difference between experimental and calculated chemical shifts, is added. In addition to the energy gradients, pseudoforces are computed. This requires the derivatives of the chemical shifts with respect to the coordinates. The pseudoforces are analytically derived from the integral expressions of the bond polarization theory. Single chemical shift values attributed to corresponding atoms are considered for structural correction. As a first example, this method is applied for proton position refinement of the D‐mannitol X‐ray structure. A crystal structure refinement with ^13^C chemical shift pseudoforces is carried out. Β© 2002 Wiley Periodicals, Inc. J Comput Chem 23: 298–305, 2002

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