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    COLLOQUIUM OF THE LABORATORY FOR COMPUTER DESIGN OF MATERIALS
        Institute for Computational Sciences and Informatics
	                      CSI 898-Sec 001  
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      Probing the structure and dynamics of biological systems, 
   Molecular Dynamics simulation & neutron scattering experiments.

                           Mounir Tarek
    Center for Neutron Research, National Institute of Standards 
                 and Technology, Gaithersburg,MD and 
        Chemistry Department, University of Pennsylvania

With the advent sophisticated methodologies, computer simulation 
has emerged as a powerful probe of the behavior of complex molecular 
systems, and has become an important alternative technique to 
investigate their structural and dynamical properties.
In this communication we focus on two areas were the use atomistic 
computer modeling is shown to assist in the interpretation of 
neutron experimental data.

First we study structural features of several molecular complexes,
comparing simulation results to neutron reflectivity data. This
technique allows extraction of scattering length density profiles 
for layered systems.  Second, we focus on dynamical properties, 
illustrated by results on globular proteins. The ranges of energy and 
momentum  transfers accessible on presently available neutron 
spectrometers correspond closely to the length and size of molecular 
dynamics (MD) simulations that are feasible nowadays for these 
molecules (ns time scale). We show that simulations are a potentially 
valuable tool for interpreting the inelastic neutron scattering data.

	               Monday , February 15 1999
                                 4:30 pm
                        Room 206, Science & Tech. I

Refreshments will be served.
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(http://www.csi.gmu.edu/lcdm/seminar/schedule.html)