Department
of Chemistry
Columbia
University
3000
Broadway, New York, NY 10027
Introduction
We study equilibrium and dynamical properties of molecules
at 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 nanoparticles.
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 ~100 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: metal nanoparticles, liposomes,
semiconductor quantum dots, clays, polymer beads, emulsions
* Biomembrane
surfaces
Dynamical molecular processes at interfaces include
* Intermolecular energy transfer
* Orientational
relaxation
* Photoisomerization
* Solvation
dynamics
Group
Members
Prof. Kenneth B. Eisenthal
( kbe1@columbia.edu
)
Dr. Yi Rao, research scientist
(yr2122@columbia.edu )
Dr. Louis Haber, post-doc scientist (lh2485@columbia.edu)
Sung Young Hong, graduate student (sh2580@columbia.edu)
Sheldon Kwok, undergraduate student (sjk2154@columbia.edu)
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