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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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          Ab initio DFT studies of boron-nitrogen compounds  
                   on massively parallel computers

                             Jens Kortus
          Physics Department, Georgetown University, and 
Center for Computational Materials Science, Naval Research Laboratory

  If fuel-cell technologies are to succeed it will be necessary to find 
a means for the safe transportation of hydrogen which implies an 
oxygen free environment.  Borazane (BH$_3$NH$_3$) forms small molecular 
crystals which may be thermally activated in order to free the borazane 
molecules. The borazane molecules subsequently react further forming 
borazine (B_3N_3H_6) and molecular hydrogen.  

  Because of this chemistry, borazane serves as an oxygen-free hydrogen 
storage compound which may have potential for use in fuel cells. To 
help guide and further understand the experiments on this material we 
have performed several ab initio investigations on the stabilities, 
reactivities and vibrational signatures of the molecular solid and gas 
phase structures. We predict reaction energies for the gas-phase 
borazane-borazine hydrogen releasing  reaction. In addition we will 
discuss several possible initial borazane-borazine reaction pathways 
and barriers to estimate the thermal stabilities of these compounds. 
Finally we examine the relative stability of the borazin end product. 
The inclusion of all degrees of freedom in this reaction, particularly 
zero point vibrations, and the use of the generalized gradient 
approximation within a density functional framework were key 
ingredients for understanding this system.

  These calculation were only possible due to the computational 
resources of the beowulf PC-cluster of the Center for Computational 
Materials Science, enabling us to carry out calculations within weeks 
which otherwise would take several month by other means. 
discussed.

                         Monday , February 7, 2000
                                  4:30 pm
                        Room 206, Science & Tech. I

Refreshments will be served.
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