Contact information
Jiahao Chen 陈家豪
MIT Department of Chemistry
Room 6-228
Cambridge, MA 02139
mit.edu email: jiahao
Stuff
Education
University of Illinois at Urbana-Champaign
| 2009 | PhD in Chemical Physics with Computational Science and Engineering option |
| 2008 | MS in Applied Mathematics with Applications to the Sciences |
| 2002 | BS in Chemistry, magna cum laude |
Research Projects
- New population analysis methods
Fluctuating-charge models
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:
- Force fields for charge-transfer excitonic states
- Hybrid fluctuating-charge and inducible dipole models
- Systematic relationships between fluctuating-charge models and density functional theory
- Automatic parameterization of polarizable, charge-transfer capable force fields