Contents |
Most of my posters and talks are on SlideShare.
Fluctuating-charge models are an inexpensive way to extend force field technology to describe polarization and charge transfer effects in molecular dynamics simulations. For my PhD, I worked on fixing spurious charge transfer in these models, where dissociated molecules would still want to transfer charge, even at infinite separation. Existing models like QEq and EEM would predict fractional charge distributions at dissociation. Without drastic measures like turning off intermolecular charge transfer, it becomes impossible to calculate reliable electrostatic properties, and dynamical simulations would see crazy things like delocalized charge fluctuation waves. We came up with the QTPIE model, which turned off long range charge transfer by attenuating the electronegativity differences as explicit functions of distance. This also turned out to be important in making polarizabilities scale correctly with system size.
I am still working on extensions on the methodology of fluctuating-charge models to:
For my bachelor's thesis, I worked with Nancy Makri at the University of Illinois at Urbana-Champaign on exciton coherence in light harvesting complex II, using path integral Monte Carlo (PIMC) to study the statistical mechanical distribution of coherence and the quasiadiabatic propagator path integral (QUAPI) method to sample its dynamical evolution. A summary of this work is available on arXiv as preprint 0812.1552.
Lots of random notes here.
Some potentially interesting collections follow.