engleski

NMR and NQR parameters of organic materials in the GIPAW density functional theory model

Theoretical methods have always been an important support in analysis of NMR measurements. However, traditional approaches for real materials, for example these based on the quantum chemistry Gaussian code, are used only for a finite and small part of a sample which then models an infinite crystal. GIPAW (Gauge Including Projector Augmented Wave) is a density functional pseudopotential method introduced by Francesco Mauri and coworkers. It is possible to use this method for molecules, clusters, surfaces, real three-dimensional crystals and amorphous materials. These approaches, as well as related methods based on the orbital magnetization, are still in development. GIPAW already produces results for NMR and NQR parameters of many materials in a good agreement with experiments. Methods based on the GIPAW pseudopotentials, if coupled with LDA(GGA)+U techniques used for studies of structural and electronic properties of strongly correlated materials, could give a very good support for experiments in solid-state NMR of correlated electronic systems. We present results for chemical shifts, as well as for coupling constants and asymmetry quadrupolar parameters, of two organic materials. The first one is ethanol, C2H5OH, where we study the molecule and the crystal. We also calculate NMR parameters of a more complex organic molecule proflavine C13H11N3 (3, 6-diaminoacridine), known as an intercalator in DNA and RNA. Computed parameters are compared with experimental data.

NMR; NQR; density functional theory; GIPAW

nije evidentirano