Document Type
Article
Publication Date
1999
Abstract
This paper describes recent results using our approach to calculating self-consistently single (SS) and multiple-scattering (MS) Debye- Waller factors (DWF) on active sites of metalloproteins. The calculation of MS DWF, together with the Feff7 program allows us to simulate ab-initio EXAFS spectra for a given temperature systems with no adjustable parameters. In our latest report (Dimakis N., and Bunker G., 1998) we calculate, using density functional and semiempirical approaches, the SS and MS DWF for small molecules and compared them to Raman, infrared and EXAFS spectra. In this report calculation of DWFs is done for tetrahedral Zn imidazole, a complex containing thirty two atoms that is similar in certain respects to active sites of many metalloproteins. Ab-initio calculation, although it is a more accurate and reliable scheme, it is not at present practical on desktop computers; computation times are weeks. Therefore as an alternative we have tried the semiempirical MNDO Hamiltonian, which is at least three orders of magnitude faster than ab-initio, and can be expected to be of reasonable accuracy because it is parameterized for organic compounds. Our approaches take advantage of commercially available molecular orbital programs. We have written additional programs which, using normal mode calculations, calculate the MS paths, and transparently interface with Fef-f'/to produce the EXAFS spectra. Results are in very good agreement with experimental data tested.
Recommended Citation
Dimakis, N., et al. “Rapid Single- and Multiple-Scattering EXAFS Debye-Waller Factor Calculations on Active Sites of Metalloproteins.” Journal of Synchrotron Radiation, vol. 6, no. 3, 3, International Union of Crystallography, May 1999, pp. 266–67, http://doi.org/10.1107/S0909049599000564
First Page
266
Last Page
267
Publication Title
Journal of Synchrotron Radiation
DOI
10.1107/S0909049599000564
Comments
© 1999 International Union of Crystallography. Original published version available at https://doi.org/10.1107/S0909049599000564