Intermolecular Dynamics in Crystalline Iron Octaethylporphyrin (FeOEP)
| Autor: | Valeriia N. Starovoitova, W. Robert Scheidt, Stephen M. Durbin, Wolfgang Sturhahn, E. Ercan Alp, Graeme R. A. Wyllie |
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| Rok vydání: | 2008 |
| Předmět: |
Models
Molecular Porphyrins Chemistry Phonon Infrared Iron Intermolecular force Molecular Conformation Crystallography X-Ray Spectrum Analysis Raman Vibration Molecular physics Article Surfaces Coatings and Films Crystallography symbols.namesake Normal mode Crystal model Materials Chemistry symbols Molecule Physical and Theoretical Chemistry Nuclear resonance vibrational spectroscopy Raman spectroscopy |
| Zdroj: | The Journal of Physical Chemistry B. 112:12656-12661 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp806215r |
| Popis: | The new technique of nuclear resonance vibrational spectroscopy (NRVS) has increased the range and quality of dynamical data from Fe-containing molecules that when combined with Raman and infrared spectroscopies impose stricter constraints on normal mode simulations, especially at lower frequencies. Going beyond the usual single molecule approximation, a classical normal-mode analysis that includes intermolecular coupling and the full crystalline symmetry is found to produce a better fit with fewer free parameters for the heme compound iron octaethylporphyrin (FeOEP), using NRVS data from polycrystalline material. Off-diagonal force constants were completely unnecessary, indicating that their role in previous single molecule fits was just to emulate intermolecular coupling. Sound velocities deduced from the calculated phonon dispersion curves are compared to NRVS measurements to further constrain the intermolecular force constants. The NRVS data by themselves are insufficient to rigorously determine all unknown force constants for molecules of this size, but the improved crystal model fit indicates the necessity of including intermolecular interactions for normal-mode analyses. |
| Databáze: | OpenAIRE |
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