Distribution of Chemical Dynamics Software

  1. 1. Gas Phase and Gas-Surface Dynamics.
  2. The computer programs and simulation models developed as part of the research supported by AFOSR were given to other scientists and this has enabled a number of important research projects. VENUS/MOPAC and the PM3-SRP PES models for O(3P) reactions with alkanes were given to scientists at Spectral Sciences, Inc. VENUS and the simulation models for rare gas atoms scattering off H-SAM surfaces were given to the Steven Sibener, John Morris, and Diego Troya research groups, which lead to several significant publications.1-3

fig1
Plot of the fraction of the initial Ar energy exchanged with the surface as a function of deflection angle x=θif, for the fast component at Ts=135K and Φi=0°. The inset indicates the incident energy and azimuthal angle. The solid line is from a fit to a binary collision model.

fig1
Experimental and calculated average product energy values as a function of polar-scattering angle in collisions of Ar with a SAM at Ecoll=56kJ/mol with a θi=60° incident angle.2

fig1
Probability distributions of the minimum height reached for the argon atoms for trajectories from SAMs on silver (open circles) and gold (filled circles).3

  1. 2. Condensed Phase Dynamics.
  2. As part of our STTR grant “Predicting Kinetic Rate Constants for Condensed Phases”, a project administered by Robert Shroll and Spectral Sciences, Inc., we developed software for QM and QM/MM condensed phase direct dynamics simulations. For the QM simulations all the atoms are represented by a quantum mechanaical (QM) electronic structure theory, while some of the atoms are represented by molecular mechanics (MM) functions for the QM/MM simulations. These simulations are performed with the VENUS/MOPAC package for semiempirical direct dynamics and VENUS/NWChem for ab initio direct dynamics. The VENUS/MOPAC and VENUS/NWChem packages are distributed via the web portal cdssim.chem.ttu.edu. The development of this software enabled the Condensed Phase Non-Equilibrium Reaction Dynamics study described above. A description of VENUS/NWChem has been accepted for publication.4

References

  1. 1. "Experiments and Simulations of Ar Scattering from an Ordered 1-Decanethiol-Au(111) Monolayer." Journal of Chemical Physics 119, 13083-13095 (2003)
    K. D. Gibson, N. Isa and S. J. Sibener
  2. 2. "Classical Trajectory Study of Collisions of Ar with Alkanethiolate Self-Assembled Monolayers: Potential Energy Surface Effects On Dynamics." Journal of Chemical Physics 122, 214712/1-12 (2005)
    B. S. Day, J. R. Morris and D. Troya
  3. 3. "Packing Density and Structure Effects on Energy-Transfer Dynamics in Argon Collisions with Organic Monolayers." Journal of Chemical Physics 122, 234714/1-10 (2005)
    B. S. Day and J. R. Morris
  4. 4. "The VENUS/NWChem Software Package. Tight Coupling between Chemical Dynamics Simulations and Electronic Structure Theory." Computer Physics Communications, accepted
    U. Lourderaj, R. Sun, S. C. Kohale, W. A. de Jong, T. L. Windus and W. L. Hase