Julie A. Gruetzmacher
Contact Information
Office:	Searle Chemical Laboratory 023
Lab:	Searle Chemical Laboratory 022
Phone:	773-834-1877
Fax:	773-702-0805
Email:	jgruetzm@midway.uchicago.edu
Education
1999:	M.S. Chemistry, University of Chicago, Chicago, IL
1997:	B.S. Chemistry, Physics minor, Carroll College, Waukesha, WI
Research Abstract
Infrared spectroscopy is a valuable tool for the study of molecular interactions, as the vibrations of molecules are sensitive to the molecular-level details of their environments. The broadband vibrational transitions of hydrogen-bonding (H-bonding) liquids are intriguing from a dynamical standpoint because the vibrational frequencies of modes involved in H-bonding can be correlated with H-bond strength; frequency-dependent dynamics may reveal correlations between H-bond structure and dynamics. We seek to understand the temporal and spectral behavior of H-bonding vibrational modes involved in processes such as proton transfer and aqueous solvation, with a particular interest in molecules in restricted environments. The processes of interest occur on femtosecond to picosecond time scales; thus, ultrashort pulses in the mid-infrared spectral region are required to time resolve these phenomena. We have developed a source of sub-65 fs mid-infrared pulses with tunability from 2800 nm to beyond 4000 nm that are suitable for these studies.
We also have used the pulse characterization technique of cross-correlation frequency-resolved optical gating (XFROG) to view infrared pulse propagation in the joint time-frequency domain and are developing this technique as a method to obtain intensity and phase information on signals from molecular responses. We have observed significant pulse distortions when samples have optical densities similar to those used in other ultrafast infrared experiments, showing that care must be taken when selecting sample conditions for experiments in which pulses have durations comparable to the dephasing time of the transition of interest. We have developed a correlation function- based finite-difference time-domain (FDTD) algorithm that combines the classical FDTD method with the correlation function formalism developed by Shaul Mukamel (Univ. Rochester) to simulate propagation effects on signals and evaluate the suitability of published correlation functions for the vibrational relaxation of the OH-stretching vibration of water.
Curriculum Vitae
Selected Publications and Works in Progress
Correlation function-based finite-difference time-domain method for simulating ultrashort pulse propagation. I. Formalism J. A. Gruetzmacher, J. Chem. Phys. in press (2003).
Correlation function-based finite-difference time-domain method for simulating ultrashort pulse propagation. II. Examination of vibrational correlation functions for the OH-stretching vibration of HDO J. A. Gruetzmacher and N. F. Scherer, in preparation for submission to J. Phys. Chem. A (2003).
Gain-switched all-acousto-optic femtosecond pulse amplifier J. A. Gruetzmacher, M. A. Horn, B. N. Flanders, X. Shang, and N. F. Scherer, submitted to Rev. Sci. Instrum. (2003).
Finite-difference time-domain simulation of ultrashort pulse propagation incorporating quantum-mechanical response functions J. A. Gruetzmacher and N. F. Scherer, Opt. Lett. 28, 573-575 (2003).
Few-cycle mid-infrared pulse generation, characterization, and coherent propagation in optically dense media. J. A. Gruetzmacher and N. F. Scherer, Rev. Sci. Instrum. 73, 2227-2236 (2002).
The vibrational spectrum of the hydrated proton: Comparison of experiment, simulation, and normal mode analysis. Jeongho Kim, Udo W. Schmitt, Julie A. Gruetzmacher, Gregory A. Voth and Norbert F. Scherer, J. Chem. Phys., 116, 737-746 (2002).
Femtosecond studies of the initial events in the photocycle of Photoactive Yellow Protein (PYP). M. A. Horn, J. A. Gruetzmacher, J. Kim, S.-E. Choi, S. M. Anderson, K. Moffat, and N. F. Scherer, in Femtochemistry, August 2001 Edition, F. C. DeSchryver, S. De Feyter, G. Schweitzer (eds.), Wiley-VCH, Weinheim, pp. 381-390.
Phosphatidylcholine monolayer structure at a liquid-liquid interface. R. A. Walker, J. A. Gruetzmacher, and G. L. Richmond, J. Am. Chem. Soc. 120, 6991 (1998).
Links
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