First Principles NMR Calculations by Fragmentation

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• 作者：Adrian M. Lee ; Ryan P. A. Bettens
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：June 14, 2007
• 年：2007
• 卷：111
• 期：23
• 页码：5111 - 5115
• 全文大小：58K
• 年卷期：v.111,no.23(June 14, 2007)
• ISSN：1520-5215

文摘

The nuclear magnetic shielding tensor is a molecular property that can be computed from first principles. Inthis work we show that by utilizing the fragmentation approach, one is able to accurately compute this propertyfor a large class of molecules. This is of great significance because the computational expense required in theevaluation of the shielding tensor for all nuclei in a large molecule is now subject to near linear scaling. Onthe basis of previous studies and this work, it is also very likely that all molecular properties that can beexpressed as derivatives of the total energy of the system are also amenable to accurate evaluation viafragmentation. If only the chemical shifts for nuclei in a small part of a large molecule are of interest, thenonly those molecular fragments containing those nuclei need to have their shielding tensors evaluated. Further,the fragmentation approach allows one to construct a database of molecular fragments that could, in principle,be used in the NMR characterization of molecules and at the same time provide possible three-dimensionalrepresentations of these molecules.