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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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          Polarization interactions in large organic molecules, 
                      molecular aggregates and solids

                             Eugene Tsiper
                Center for Computational Materials Science 
                  Naval Research Laboratory,Washington DC  

Weakly bound molecular systems appear in many areas of modern science
ranging from molecular crystals in organic electronics to molecular
aggregates in biophysics.  Such systems pose significant difficulties
to conventional computational methods.  Long range Coulomb forces,
small transfer integrals and localized nature of charges make
polarization interactions a major effect, with energy scale of the
order of 1 eV.  I will describe our recent approach which treats
individual molecules rigorously as quantum-mechanical systems subject
to classical fields of other molecules.  Molecular fields are
described in terms of minimal atomic multipole expansion.  Atom-atom
polarizability tensor is introduced to account for self-consistent
charge redistribution within individual molecules.  Applied to
molecular crystals, the approach allows to compute polarization
contribution to sublimation energies, transport gaps and positions of
charge-transfer states, dielectric tensors.  I will also discuss
applications to intermolecular forces, particularly to hydrogen
bonding and van der Waals interactions.

                         Monday , November 17, 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
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