Ph.D, Columbia University, New York
Quantum Chemistry - Electronic Structure Modeling
Our group analyzes complex chemical systems for which proper description requires an electronic structure-based approach. We consider excited state dynamics, intermolecular weak interactions, and reaction mechanisms. Complex processes that we study include electron transfer and transport and their coupling to vibrations or to other time dependent (TD) external forces. Other systems that we study include molecules with biological functionality. For example, we study proton transfer reactions and catalytic centers in enzymes.
In a main research effort, we study electron transport (ET) processes through molecular and nanoscale bridges. The complexity in modeling ET is due to the non-equilibrium (NE) conditions that result in current flow. Reliable representation of these NE effects requires the development of specialized electronic structure approaches. We develop and employ cutting-edge modeling techniques to gain insight into specific molecular/nanoscale bridges and related physical phenomena. The impact of our research is due to the study of electron transport of experimental systems and due to constructing important methodological foundations for treating time-dependent aspects of transport processes. Our studies have enabled us to provide insight into the ET process, explain experimental measurements and make predictions that guide new experiments.
Our current research focus aims to advance energy conversion applications. We study materials with potential to improve the conversion efficiency. We implement high-level models and derive new methodologies to study charge transfer in photovoltaic (PV) materials and electron transport in thermoelectric applications using molecular bridges in collaboration with experimentalists. We model the effects of electron-phonon and electron-photon coupling on electron transport through the interfaces. Along with our collaborators we extend electron transport treatments to models that are larger than the currently accessible systems.
We pursue density functional theory based models to study energy and electron transport properties of molecular thin films and nanostructured interfaces using first-principles-based models. We pursue novel time-dependent density functional theory (TD-DFT) that are capable of reliably treating charge-transfer processes that underlie the photovoltaic activity.
Further details can be obtained at our Research Group Website.
Scholarly, Creative & Professional Activities
- Ab-initio study of the emissive charge-transfer states of solvated chromophore-functionalized silsesquioxanes, Zheng, S. and Phillips, H. and Geva, E. and Dunietz, B. D., J. Amer. Chem. Soc, 134 (2012) 6944-6947.
- Examining Symmetry-Hidden Charge Transfer Excitations using Range-Separated Density Functionals, Phillips, H. and Geva, E. and Dunietz, B. D., J. Chem. Theo, Comp., Accepted (2012).
- End group induced charge transfer in molecular junctions: Effect on thermopower, Balachandran, R. and Reddy, P. and Dunietz, B. D. and Gavini, V., J. Chem. Phys. Lett., Accepted (2012).
- Effect of Length and Contact Chemistry on the Electronic Structure and Thermoelectric Properties of Molecular Junctions, Aaron Christopher Tan , Janakiraman Balachandran , Seid Hossein Sadat , Vikram Gavini , Barry D. Dunietz , Sung-Yeon Jang , and Pramod Reddy J. Amer. Chem. Soc., 132 (2011) 2914-18.
- Efficiency of thermoelectric energy conversion in biphenyl-dithiol junctions: Effect of electron-phonon interactions, Nikolai Sergueev, Seungha Shin, Massoud Kaviany and Barry D. Dunietz, Phys. Rev. B., 83 (2011) 195415.
- Bias effects on the electronic spectrum of a molecular confined and biased bridge, Heidi Philips, Alex Prociuk and Barry D. Dunietz, J. Chem. Phys., 134 (2011) 054708
- Photo-induced absolute negative current in a molecular electronic system, Alex Prociuk and Barry D. Dunietz, Phys. Rev. B., 82 (2010) 125449.
- Gating dependence of single molecule field effect transistors on contact symmetry, Trilisa Perrine and Barry D. Dunietz, J. Amer. Chem. Soc., 132 (2010) 2914-2918.
- Enhanced Conductance via Induced pi-Stacking Interactions in Cobalt(II) Terpyridine Bridged Complexes, Trilisa M. Perrine, Timothy Berto and Barry D. Dunietz J. Phys. Chem. b., 112 (2008) 16070-16075.
- Time-dependent current through electronic channel models using a mixed time-frequency solution of the equations of motion, Alexander Prociuk and Barry D. Dunietz Phys. Rev. B, 78 (2008) 165112.