Rene Nome
Contact Information
Office:	GCIS ESB 009
Lab:	GCIS ESB
Phone:	773-834-1877
Fax:	773-702-0805
Email:	ranome@uchicago.edu
Education
2002:	M.S. Chemistry, Federal University of Santa Catarina, Brazil
2000:	B.S. Chemistry, Federal University of Santa Catarina, Brazil
Research Abstract
Vibrational Relaxation of the O-H Stretching Vibration of Water
The correlation function-based finite-difference time-domain (CF-FDTD) method (J. A. Gruetzmacher, J. Chem. Phys., 119(3), 1590 (2003)) is being used to simulate the resonant linear propagation of ultrashort mid-infrared pulses through optically dense samples of HDO in liquid D2O. Simulations using response functions for the OH-stretching vibration, obtained from nonlinear spectroscopic studies reported by others, show that the details of the lineshape function are manifested in the resulting field patterns. Comparison of simulations with experimentally-determined fields allows assessing the accuracy of various correlation functions in describing fast vibrational dynamics. Both time and frequency domain pictures of the free-induction decay-modified pulse fields are constructed, permitting further characterization. Spectra obtained from propagated fields show different levels of agreement with predicted absorption spectra, and the extent to which spectra agree depends on the memory contained in the response function. These comparisons raise an issue that has garnered little attention: whether the spectrum acquired with incoherent light is necessarily the appropriate linear absorption spectrum to use as a benchmark for measurements with coherent radiation.
Photoinduced Dynamics of Systems of Biological Relevance
Biological photoreceptors are optimally suited to study the role of dynamical alterations in protein structure in relation to their function. Understanding the initial phase of the response of a photoreceptor to light absorption, which typically occurs on femtosecond time scales, is a prerequisite for understanding the formation of its signaling state at the molecular level. Upon photoexcitation these receptor proteins can feed their signals into distinct photobiological response pathways and a fundamental knowledge of the energy distribution mechanisms involved is essential to understand the global protein function. Finally, another key question is how the chromophore dynamics are modified by the protein. With such questions in mind, we want to examine the dynamics of biological photoreceptors in the early stages of relaxation immediately after photoexcitation by means of sub-100fs pump-probe (one- and two- color) and polarization anisotropy measurements.