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Chemical shift driven geometry optimization
Author(s) -
Witter Raiker,
Prie Wolfram,
Sternberg Ulrich
Publication year - 2001
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.10012
Subject(s) - force field (fiction) , energy minimization , chemical shift , molecular geometry , bond length , chemical bond , position (finance) , polarization (electrochemistry) , field (mathematics) , chemistry , computational chemistry , molecule , geometry , physics , crystal structure , crystallography , mathematics , quantum mechanics , finance , pure mathematics , economics
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. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 298–305, 2002