XAFS Debye-Waller Factors Temperature-Dependent Expressions for Fe+2-Porphyrin Complexes

Journal Article · Fri Feb 02 00:00:00 EST 2007 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2644517· OSTI ID:21054624

Dimakis, Nicholas ^[1]; Bunker, Grant ^[2]

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1. University of Texas-Pan American, Edinburg, TX 78539 (United States)
2. Illinois Institute of Technology, Chicago IL 60616 (United States)

We present an efficient and accurate method for directly calculating single and multiple scattering X-ray absorption fine structure (XAFS) thermal Debye-Waller factors for Fe+2 -porphiryn complexes. The number of multiple scattering Debye-Waller factors on metal porphyrin centers exceeds the number of available parameters that XAFS experimental data can support during fitting with simulated spectra. Using the Density Functional Theory (DFT) under the hybrid functional of X3LYP, phonon normal mode spectrum properties are used to express the mean square variation of the half-scattering path length for a Fe+2 -porphiryn complex as a function of temperature for the most important single and multiple scattering paths of the complex thus virtually eliminating them from the fitting procedure. Modeled calculations are compared with corresponding values obtained from DFT-built and optimized Fe+2 -porphyrin bis-histidine structure as well as from experimental XAFS spectra previously reported. An excellent agreement between calculated and reference Debye-Waller factors for Fe+2-porphyrins is obtained.

• OSTI ID: 21054624
• Journal Information: AIP Conference Proceedings, Vol. 882, Issue 1; Conference: XAFS13: 13. international conference on X-ray absorption fine structure, Stanford, CA (United States), 9-14 Jul 2006; Other Information: DOI: 10.1063/1.2644517; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
COMPUTERIZED SIMULATION
DEBYE-WALLER FACTOR
DENSITY FUNCTIONAL METHOD
FINE STRUCTURE
HISTIDINE
IRON COMPOUNDS
IRON IONS
MULTIPLE SCATTERING
PHONONS
PORPHYRINS
TEMPERATURE DEPENDENCE
VARIATIONS
X-RAY SPECTRA
X-RAY SPECTROSCOPY