Time: Aug. 14th 2014 14:00 PM
Location: Meeting room 306,Laboratory of Aerospace Catalysis and New Materials
Lecturer: Dr. Esen Ercan Alp
Advanced Photon Source, Argonne National Laboratory, Argonne,USA
Abstract
This is the 56th anniversary of the discovery of M?ssbauer effect, and the 30th anniversary first observation of nuclear resonant scattering using synchrotron radiation. In the last two decades, with availability of synchrotron sources worldwide, the nature of the M?ssbauer spectroscopy has changed in many ways. For example, experiments in studying lattice dynamics of materials show substantial modification as a function of pressure and temperature. Hence, when a new class of materials are discovered, inelastic x-ray scattering (IXS) and nuclear resonant inelastic x-ray scattering (NRIXS) can help measure changes in sound velocity, shear velocity, specific heat, Gruneisen constant, and elastic constants. Measurement of combination of synchrotron M?ssbauer hyperfine parameters with identifiable signature of vibrational mode of a particular ligand makes this technique powerful for catalysis studies.
There are now three usable beamlines at the APS. They have a unique combination of high-pressure, high and low temperature, and x-ray diffraction. Inelastic nuclear resonant scattering and synchrotron M?ssbauer spectroscopy (SMS) for Kr, Fe, Eu, Dy and Sn nuclear resonances. Recent research results will be presented. Selected publications:
1) "Observation of the Fe-CN and Fe-CO vibrations in the active site of [NiFe] hydrogenase by nuclear resonance vibrational spectroscopy" Angew. Chem. Int. Ed. 52, 724 (2013).
2) "Nuclear resonance vibrational spectroscopic and computational study of high-valent diiron complexes relevant to enzyme intermediates" PNAS 110, 6275 (2013).
3) "Nuclear resonance vibrational spectra of five-coordinate imidazole-ligated iron(II) porphyrinates" Inorg. Chem. 51, 1359 (2012).
4) "Heme-protein vibrational couplings in cytochrome c provide a dynamic link that connects the heme-iron and the protein surface," PNAS 109, 8896 (2012).
5) "Synchrotron-derived vibrational data confirm unprotonated oxo ligand in myoglobin compound II" JACS 130, 1816 (2008).
Introduction
Ph.D. Southern Illinois University, Carbondale, Illinois,1984, Physics
2004-present: Senior Scientist, X-Ray Science Division, Argonne National Laboratory
Research Experience:
M?ssbauer Spectroscopy; X-ray absorption spectroscopy, Polarized XANES; Nuclear resonant scattering of synchrotron radiation; Nanomaterials for catalysis and energy applications
Contacts:Sun Hui 89161