Nanotechnology

Data on chemical physics reported by researchers at Jackson State University

  2009 JUN 29 - (VerticalNews.com) -- According to recent research from the United States, "The quality of the newly added, empirical dispersion correction in density functional theory (DFT) calculations is examined for several supramolecular complexes of fullerene (C-60) with free-base and metal porphyrins (Por). The benzene dimer (C6H6)(2), naphthalene dimer (C10H8)(2), and anthracene dimer (C14H10)(2) were also included in the study for comparison."

  "Three density functionals, two damping functions, and two types of basis sets were employed in the computations. The estimated dispersion energies in the fullerene-porphyrin systems are rather large, ranging from 0.5 eV in C-60 center dot ZnP to 1 eV in C-60 center dot H2TPP. Any dispersion-corrected DFT (DFT + E-disp) method is shown to perform well for C-60 center dot H2TPP, C-60 center dot ZnTPP, and C-60 center dot ZnP, where the intermolecular distances are relatively large. But large basis sets, e. g. TZP (triple-zeta + one polarization function), are required in order to obtain reliable results with DFT + E-disp. In the case of C-60 center dot FeP, where the intermolecular distance R is short, the DFT + E-disp calculated R depends on the damping function as well as on the DFT method, and all the DFT + E-disp calculations lead to significant changes in the relative energies of the various spin states. The quality of the DFT + E-disp calculated results on C-60 center dot FeP is hard to judge here without detailed experimental data on a C-60 center dot FePor complex," wrote M.S. Liao and colleagues, Jackson State University.

  The researchers concluded: "Owing to error cancellation, the pure DFT calculations with a smaller DZP (double-zeta + one polarization function) basis set without any correction are shown to give quite accurate results."

  Liao and colleagues published their study in Physical Chemistry Chemical Physics (Dispersion-corrected DFT calculations on C-60-porphyrin complexes. Physical Chemistry Chemical Physics, 2009;11(21):4365-4374).

  For additional information, contact M.J. Huang, Jackson State University, Dept. of Chemical, POB 17910, Jackson, MS 39217, USA.

  Publisher contact information for the journal Physical Chemistry Chemical Physics is: Royal Society Chemistry, Thomas Graham House, Science Park, Milton Rd., Cambridge CB4 0WF, Cambs, England.

  Keywords: Emerging Technologies, Fullerenes, Nanotech, Nanotechnology, Supramolecular, Supramolecular Complexes, Physics, Jackson State University.

  This article was prepared by VerticalNews Nanotechnology editors from staff and other reports. Copyright 2009, VerticalNews Nanotechnology via VerticalNews.com.