Eisenthal Group

Introduction
    We study equilibrium and dynamical properties of molecules at liquid interfaces.  Many important chemical processes occur at liquid interfaces.  Examples include cell membranes which host a variety of vital reactions in biology and life science, air/water interface (environmental importance), solid/liquid and liquid/liquid interfaces in catalysis and electrochemistry, surfaces of self-organized structures such as phospholipid bilayers, liposomes, and micelles, and surfaces of colloids and microparticles.
    Experiments performed in our lab are a unique combination of ultrafast (femtosecond) and surface-selective capabilities.
    We use nonlinear optical spectroscopies to selectively probe molecules in the the very thin interfacial region (~10 Å).  The second order nonlinear optical processes of Second Harmonic Generation (SHG) and Sum Frequency Generation (SFG) are symmetry-forbidden in bulk media, but allowed at interfaces.
     In our experiments we use femtosecond lasers to perform ultrafast time-resolved measurements.  This allows to observe motions and reactions of molecules at interfaces in real time.  Our current time resolution is ~140 fs.
    Here are examples of static molecular properties at liquid interfaces that have been characterized in our group:
        * pK of acids and bases
        * Orientation of adsorbed molecules
        * Electronic spectra
        * Polarity
        * Surface potential of charged interfaces
        * Surface properties of microscopic particles: liposomes, semiconductor colloids, clays, polymer beads, emulsions
        * Biomembrane surfaces
    Dynamical molecular processes at interfaces include
        * Intermolecular energy transfer
        * Orientational relaxation
        * Photoisomerization
        * Solvation dynamics

 Research projects

 Experimental setups

 Recent publications

Group Members
Prof.Kenneth B.Eisenthal  ( eisenth@chem.columbia.edu )
   Dr. Xiaoming Shang, research scientist (xshang@chem.columbia.edu)
   Kim T. Nguyen, graduate student (ktn12@columbia.edu)
   Jian Liu, graduate student (jl2157@columbia.edu)
   Eric MacArthur, graduate student (em2141@columbia.edu)

Recent Graduates
    Dr. Yan Liu, Duke University postdoc
   Dr. Elsa C.-Y. Yan, UC Berkeley postdoc
   Dr. Saonli Basu, teaching in India
   Dr. Alex Benderskii, assitant professor at Wayne State University
   Dr. Zhenhui Zhang, editor at Chemical Abstracts

Location
  Havermeyer Hall             Offices:  Room 604-605                Laser Labs:  Room 603                Wet Lab: Room 610
  Department of Chemistry,  Columbia University, 3000 Broadway, New York, NY 10027
  Phone: (212) 854-2094