I have been working on material chemistry and I often have used DFT calculation in order to optimize the geometry of the molecules for which I use B3LYP-6-31G* as input command. Recently I have synthesized some microporous materials for which I need to determine the pore size using DFT. In literature people have used Non-local density functional theory (NL-DFT). Could any one help me by giving the exact input command for this calculation?
Well, B3LYP is certainly non-local in the sense, that its exchange-correlation functional depends not only on the value of electron density, but also on its derivatives. The Becke three-parameter functional (B3) and Lee-Yang-Parr correlation functional (LYP) include both local and non-local terms: see http://www.gaussian.com/g_tech/g_ur/k_dft.htm and the corresponding paper for exact terms.
B3LYP seems a decent choice for your calculations, though it's a bit dated. I would suggest switching to more modern functionals, like Truhlars M06 (or newer ones) and include dispersion corrections. In your case using long-range correlated functionals like wB97XD or CAM-B3LYP would also make more sense.
The NL-DFT procedure used in porous solids, is not the one available in the quantum chemistry packages.
Micromeritics (company that makes adsorption apparatus) has been leading this NL-DFT area. You can read more, including the relevant literature for calculating adsorption isotherms form DFT in their NL-DFT history:
http://www.micromeritics.com/Library/DFT-NLDFT-Density-Functional-Theory/A-Brief-History-of-Density-Functional-Theory-Applied-to-Extracting-Information-from-the-Physical-Adsorption-Isotherm.aspx
http://www.micromeritics.com/Library/DFT-NLDFT-Density-Functional-Theory/A-Brief-History-of-Density-Functional-Theory-Applied-to-Extracting-Information-from-the-Physical-Adsorption-Isotherm.aspx
Bartosz Trzaskowski and Fernando Vallejos-Burgos, thanks a lot for your suggestions and guidance. I will read the links and follow the informations available there..have a good day!!!
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