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   COLLOQUIUM OF THE LABORATORY FOR COMPUTER DESIGN OF MATERIALS
                   School of Computational Sciences
                           (CSI 898-Sec 001)
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               "Towards the Development of a Theory of 
                 Reaction Rates for Large Molecules"

                          Marc R. Nyden
               Building and Center for Fire Research
         National Institnute of Technology, Gaithersburg, MD


 Computational quantum chemistry, ideal-gas statistical mechanics, and 
 statistical reaction rate theories (SRRT's) - so powerful for 
 gas-phase kinetics - are much more limited when applied to large 
 molecules. There are serious questions about how energy is transferred 
 in the condensed phase and whether the key assumption of SRRT's, that 
 the energy from molecular collisions is randomized before there is a 
 reaction, remains valid. A related concern is how to define the 
 reactive center and to account for the myriad of time-dependent 
 potential energy interactions that can affect reaction rates. 
 Furthermore, the dynamics of systems consisting of long linear 
 molecules, such as polymers, are dominated by low frequency, 
 anharmonic rovibrations, which are not efficiently handled in standard 
 formulations of quantum statistical mechanics. On the other hand, 
 molecular dynamics is computationally tractable, at least when used in 
 conjunction with a force field description of the potential energy, 
 and its validity is independent of assumptions about the distribution 
 of energy because the exchange of energy between vibrational modes is 
 an integral part of the calculation.
		
                Monday , September 15, 2003
                         4:30 pm
                Room 206, Science & Tech. I

Refreshments will be served at 4:15 PM.
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Find the schedule at http://www.scs.gmu.edu/lcdm/seminar/schedule.html