Hosted by: Deyu Lu

Center for Functional Nanomaterials Seminar David Prendergast Dynamics in materials evident through first-principles interpretation of X-ray spectroscopy The Molecular Foundry, Lawrence Berkeley National Laboratory Thursday, May 21, 2015 11:00 a.m. Bldg. 735 â€" Conf. Rm. A The intrinsic ultrafast time scale of core-level excitations permits the use of X-ray spectroscopy to sample energy-relevant dynamics in materials. With the advent of X-ray free electron lasers, and even table-top X-ray sources, pump-probe measurements allow us to drive particular excitations externally and follow a given system response. Examples will be presented relevant to solar harvesting and the fundamental interactions that thermalize excited electron-hole distributions. Additionally, the intrinsic dynamics of materials around their thermodynamic equilibria are continually being sampled using typical synchrotron X-ray sources. In fact, without sampling the thermodynamic distribution, simulated spectra may lack particular features related to defect populations, interconversion of chemical species, momentary broken symmetry, etc. Through a combination of theoretical predictions and interpretation of experiment, it is possible to begin to disentangle the wealth of information in X-ray spectroscopy. Examples will be given from recent work in the context of electrochemical energy storage. Host: Deyu Lu Joann Tesoriero Center for Functional Nanomaterials P.O. Box 5000 Upton, NY 11973 631-344-7791 631-344-7769 tesoriero@bnl.gov