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An electron force field for simulating large scale excited electron dynamics

Citation

Su, Julius Tsu-li (2007) An electron force field for simulating large scale excited electron dynamics. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-05032007-151410

Abstract

We introduce an electron force field (eFF) that makes simulation of large scale excited electron dynamics possible and practical. The forces acting on thousands of electrons and nuclei can be computed in less than a second on a single modern processor.

Just as conventional force fields parameterize the ground state potential between nuclei, with electrons implicitly included, electron force fields parameterize the potential between nuclei and simplified electrons, with more detailed degrees of freedom implicitly included. The electrons in an electron force field are Gaussian wave packets whose only parameters are its position and its size.

Using a simple version of the electron force field, we compute the dissociation and ionization behavior of dense hydrogen, and obtain equations of state and shock Hugoniot curves that are in agreement with results obtained from vastly more expensive path integral Monte Carlo methods. We also compute the Auger dissociation of hydrocarbons, and observe core hole decays, valence electron ionizations, and nuclear fragmentation patterns consistent with experiment.

We show we can describe p-like valence electrons using spherical Gaussian functions, enabling us to compute accurate ionization potentials and polarizabilities for first row atoms, and accurate dissociation energies and geometries of atom hydrides and hydrocarbons.

We show also that we can describe delocalized electrons in a uniform electron gas using localized eFF orbitals. We reproduce the energy of a uniform electron gas, including correlation effects; and following the historical development of density functional theory, we develop a preliminary eFF that can compute accurate exchange and correlation energies of atoms and simple molecules.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Auger; correlation; electron pairs; exchange; excited state dynamics; Gaussian; kinetic energy; molecular dynamics; path integral; Pauli; plasma; reactive force field; uniform electron gas; wave packet
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Awards:The Herbert Newby McCoy Award, 2007
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Goddard, William A., III
Thesis Committee:
  • Stoltz, Brian M. (chair)
  • Gray, Harry B.
  • Marcus, Rudolph A.
  • Goddard, William A., III
Defense Date:12 April 2007
Record Number:CaltechETD:etd-05032007-151410
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-05032007-151410
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1598
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:16 May 2007
Last Modified:11 Mar 2013 23:39

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