[MOS] MOS March 29, 2005

[Zina Queen]

Seminar on
Modern Optics and Spectroscopy

Tim Zwier, Purdue University

Single conformation vibrational spectroscopy and isomerization dynamics

March 29, 2005
12:00 - 1:00 p.m.
Grier Room  34-401


Abstract


Conformational isomerization is an important class of unimolecular 
reaction which encompasses situations ranging from simple cis-trans 
isomerization in a double minimum potential well to the staggering 
complexity associated with the potential energy landscape for protein 
folding.  In studies of conformational isomers, the field of 
molecular spectroscopy has traditionally focused attention on the 
minima on the potential energy surface, since this is where the bulk 
of the population resides.  However, if one is interested in 
understanding the kinetics or dynamics of such processes, it is the 
barriers to isomerization that are of primary importance.  In this 
talk, I will describe recent results from our group using population 
transfer spectroscopy, a laser based pump-probe method that measures 
the energetic thresholds for isomerization between specific X_Y 
reactant-product pairs.  From a series of such measurements, it is 
possible to map out the relative energies of the key stationary 
points (both minima and transition states) on the potential energy 
surface.  Among the examples to be discussed are studies of 
conformational isomerization in isolated flexible biomolecules and 
water-containing complexes, including cases in which the 
isomerization involves motion of a single solvent molecule between 
hydrogen bonding sites on a solute.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.mit.edu/pipermail/mos/attachments/20050325/4c72d364/attachment.htm