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Nucleation and Growth of SWNTs Studied by QM/MD Simulations
 Stephan Irle,1
Guishan Zheng,1 Zhi Wang,1 Marcus Elstner,2 Keiji Morokuma1

 


1Cherry L. Emerson Center for Scientific Computation and
Department of Chemistry, Emory University, Atlanta, GA 30322
 2Department of Physics, University of Paderborn, Paderborn, Germany

Mechanical Systems Innovation 11th Open Seminar
The University of Tokyo, 2005/10/18
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DFTB/MD study of high-T carbon chemistry

  • Quantum mechanics is needed to describe the effect of conjugation that controls the chemistry of sp2 carbon clusters.
  • MM, even bond-breaking MM, is not appropriate because it does not include the delocalized nature of the quantum world.


  • DFTB calculates the force on the fly during MD
  •   (roughly speaking, 103 slower than MM; 103 faster than DFT)


  • Velocity Verlet Integrator (step size: 50 au = 1.2 fs)


  • Isokinetic ensemble: Velocity is universally scaled at averagely every five steps (10% scaling after every ten steps + randomly 10% scaling) (currently)


  • Code is parallelized on EMSL’s MPP2 but scales well only from ~1000 atoms


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