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         SEMINAR OF THE LABORATORY FOR COMPUTER DESIGN OF MATERIALS
           Institute for Computational Sciences and Informatics
		CSI 929  (http://science.gmu.edu/physics/)
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    Theoretical Determination of Potential Hazards in the Handling of 
                       Aged AC and CK Munitions

       Betsy M. Rice, Sharmila V. Pai, and Cary F. Chabalowski 
      U.S. Army Research Laboratory, Aberdeen Proving Ground, MD 

Agents CK (ClCN) and AC (HCN) were standard and substitute
fill, respectively, of chemical munitions during World War II and were 
mass produced during that era.   Excavation of abandoned chemical
warfare munitions dumps for environmental cleanup have uncovered old
munitions, some of which are assumed to contain CK or AC. There have
been reports that containers of aged CK and AC have spontaneously
exploded. An understanding of the chemistry of these agents is necessary
before handling of old munitions for demilitarization can be safely
accomplished.  It is well known that the association reactions of
these compounds to form cyclic trimers are exothermic, but occur very
slowly under thermal conditions.   A sudden acceleration of this 
slow exothermic polymerization could result in rapid heat and pressure
release, resulting in explosion.  We performed quantum mechanical
calculations of critical points on the potential energy surfaces to
determine if the features support this hypothesis.

Quantum mechanical calculations [ab initio and Density Functional Theory
(DFT)] were performed to investigate reaction mechanisms for formation
and decomposition of the six-membered rings C3N3X3, where X denotes Cl
or H. C3N3Cl3 (cyanuric chloride) and C3N3H3 (sym-triazine) are the
polymerization products of agents CK (ClCN) and AC (HCN).  The
calculations presented here determine energy release upon reaction,
activation barriers and details of the reaction mechanisms for the
polymerization of these agents.  The calculations investigate concerted
triple association and step-wise addition reactions leading to the
trimers, and provide information on the low-energy pathway to
polymerization.  Formation of tetramers were also investigated.

	               Monday , November 25 1996
                               5:00 pm
                       Room 206, Science & Tech. I
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