Robin M. Hochstrasser
Donner Professor of Physical Sciences
Physical Chemistry
Office: 258 N
Phone: (215) 898-8410
Email: hochstra
sas
upennedu
Jump to: Research Statement | Education and Academic History | Selected Publications
Research Statement
A main focus is on the dynamics of structural change. Methods are sought that can determine the atomic level structure of molecules in the solution phase while they are undergoing conformational motions or chemical reactions. Such research involves nonlinear infrared spectroscopy and properties of single molecules. Femtosecond lasers are used to explore new linear and nonlinear properties of molecular systems. Processes such as electronic and vibrational energy transfer, electron and proton tunneling and phase relaxation in solids, ultrafast conformational processes in liquids and vibrational energy relaxation in condensed phases are studied. New laser techniques are also used to study protein dynamics, especially of peptides, small proteins, including those whose functions can be triggered by optical pulses. The research uses femtosecond pulsed lasers and high power tunable lasers for nonlinear studies. These and other modern techniques are used for studies of optical processes undergone by molecular systems of many types. An important goal is to bring the new experimental results into relationship with theory such as molecular dynamics simulations and quantum mechanics.
Two-Dimensional Infrared Spectroscopy
Infrared analogues of 2D NMR experiments are being developed in which the coupling between the vibrations mimics the coupling between the spins in NMR. Nonlinear spectroscopies such as the photon echo, facilitate experiments in which these couplings show up as cross peaks in a 2 D spectrum. The magnitudes of the couplings can be used to determine the structure of the network of vibrators giving rise to the signal.
Single Molecule Experiments
Imaging and fluorescence spectroscopy experiments on single molecules, proteins, assemblies of molecules and whole cells are carried out using modified forms of confocal microscopy. Recent work on the light harvesting complexes of photosynthesis, on protein folding and nucleic acid dynamics has shown structural effects that could not be observed from bulk experiments. A main topic of current research is conformational dynamics of single proteins. See RLBL homepage for more information.
Education and Academic History
- Donner Professor of Physical Sciences, Director of the NIH Laser Research Resource since 1981. B. Sc. Applied Chemistry, Herriot-Watt University, 1952; Ph.D. Edinburgh University, Scotland 1955; Royal Air Force, Pilot Officer 1955-57; Instructor in Chemistry, University of British Columbia, Canada 1957-60; Research Fellow, National Research Council of Canada 1960, Research Associate, Florida State University, 1960; Assistant Professor, University of British Columbia 1961-63; Associate Professor, University of Pennsylvania, 1963-67; Professor of Chemistry, 1967-68; Blanchard Professor of Chemistry, 1968-83; Donner Professor of Physical Sciences, 1983-present; Fellow, American Academy of Arts and Sciences, 1982; Member, National Academy of Sciences, 1982; Alfred P. Sloan Fellow, 1968; J.S. Guggenheim Fellow, 1972; Alexander Humboldt Prize, 1978; Faraday Society Bourke Medal, 1980; Hinshelwood Lecturer, Oxford University, 1982; ACS, Phila. Section Award, 1990; Peter Debye Award, 1996; Ellis R. Lippincott Award; Bright Wilson Award, 1998; The Franklin Medal in Chemistry, 2003.
Selected Publications
J. Tang, E. Mei, C. Green, J. Kaplan, W.F. DeGrado, A.B. III Smith, R.M. Hochstrasser “Probing structural dynamics of individual calmodulin: peptide complexes in hydrogel by single molecule confocal microscopy” J. Phys. Chem. B (in press)C. Fang, J. Wang, Y. S. Kim, A. K. Charnley, W. Barber-Armstrong, A. B. Smith III, S. M. Decatur, R. M. Hochstrasser “Two-dimensional infrared spectroscopy of isotopomers of an alanine rich alpha-helix”, J. Phys. Chem. B, 108, 10415-10427 (2004)
S. Gnanakaran, R. M. Hochstrasser, and A. E. García “Nature of structural inhomogeneities on folding a helix and their influence on spectral measurements” Proc. Natl. Acad. Sci. USA, 101, 9229-9234 (2004)
I. V. Rubstov, J. Wang, R. M. Hochstrasser “Dual-frequency 2D-IR spectroscopy heterodyned photon echo of the peptide bond”, Proc. Natl. Acad. Sci. USA 100 (10), 5601-5606 (2003).
N-H. Ge, M. Zanni, R.M. Hochstrasser, "Effects of Vibrational Frequency Correlations on Two-Dimensional Infrared Spectra” J. Phys. Chem. 106, 962-972 (2002).
M. T. Zanni, R.M. Hochstrasser "Two-dimensional infrared spectroscopy: a promising new method for the time resolution of structures" Curr. Opin. Struct. Biol. 11, 516-522 (2001)
