Research Focus |

The research goal of the Prezhdo group is to obtain a theoretical understanding at the molecular level of chemical reactivity and energy transfer in complex condensed-phase chemical and biological environments. This requires the development of new theoretical and computational tools and the application of these tools to challenging chemical problems in direct connection to experiments. Quantum mechanics, in principle, may be used to describe any chemical process. Its application to systems containing more than a dozen atoms, however, is nearly impossible due to computational constraints. Classical mechanics, on the other hand, may be easily applied to systems of thousands of atoms. Fortunately, in a given chemical system, only a small subset of the particles involved must be treated quantum-mechanically. This has allowed our group to develop a number of mixed quantum- classical approaches that are suitable for different situations. Quantized Hamilton Dynamics, for example, provides a beautiful and remarkably simple extension of classical mechanics that incorporates zero-point motion, tunneling, dephasing and other quantum effects. The Stochastic Mean Field approach deals with chemical reactions involving quantum transitions, such as absorption and emission of light, and conversion of light and electric energy to forming and breaking chemical bonds. Chemical versions of the Schrodinger Cat paradox, the "watched pot never boils", and quantum Zeno effects are other important phenomena that may be modeled with the Stochastic Mean Field approach. The Bohmian or hydrodynamic interpretation of quantum mechanics is used to couple quantum and classical variables and to interpret results in terms of intuitive particle trajectories. These varied quantum-classical approaches are being implemented within the framework of time-dependent density functional theory. The Prezhdo group pioneered ab initio real-time simulations of the ultrafast electron transfer across the molecule-semiconductor interface that drives Gratzel-type solar cells. Organic-inorganic interfaces are critical in molecular electronics and remain the field's least understood components. We have established electron-transfer mechanisms that suggest ways to improve solar cell efficiencies. Motivated by recent experiments, we are modeling charge dynamics in semiconductor and metallic nanoparticles, carbon nanotubes and nanoribbons, and related nanoscale systems. Time-domain atomistic simulations of interactions between charges, spins and phonons in these materials create the theoretical basis for photovoltaic devices, optical and conductance switches, quantum wires, logic gates, miniature field-effect transitions and lasers. Our group has developed the simplest and most used model of biological catch-binding, a fascinating biological phenomenon whereby the application of a pulling force increases bond lifetime (!). We created a physically intuitive description of catch-binding and derived universal laws that unite experimental data obtained through different pulling regimes. We are investigating the atomic origin of catch-binding by steered molecular dynamics and study other counter-intuitive force- induced effects in molecular biology, such as force- induced allostery. New generations of electro-optic devices based on polymers showing order-disorder transitions are being designed by colleagues in Chemistry and Chemical Engineering. Our group developed a statistical- mechanical model of the ordering that clearly explains how the efficiency of the polymeric materials depends on molecular structure, temperature, electric field and other tunable parameters. Members of the Prezhdo group use both pen-and-paper and computers in their research.
View full publication list in Dr. Prezhdo group website Akimov, Alexey V., and Oleg V. Prezhdo. "Large-Scale Computations in Chemistry: A Bird’s Eye View of a Vibrant Field." Akimov, Alexey V., and Oleg V. Prezhdo. "Theory of Nonadiabatic Electron Dynamics in Nanomaterials." Encyclopedia of Nanotechnology (2015). pp 1-20 Akimov, Alexey V., Dhara Trivedi, Linjun Wang, and Oleg V. Prezhdo. "Analysis of the Trajectory Surface Hopping Method from the Markov State Model Perspective." Akimov, Alexey V., and Oleg V. Prezhdo. "Theory of solar energy materials." Akimov, Alexey V., and Oleg V. Prezhdo. "Analysis of self-consistent extended Hückel theory (SC-EHT): a new look at the old method." Akimov, Alexey V., Ryoji Asahi, Ryosuke Jinnouchi, and Oleg V. Prezhdo. "What Makes the Photocatalytic CO2 Reduction on N-doped Ta2O5 Efficient: Insights from Nonadiabatic Molecular Dynamics." Prezhdo, Victor, Karol Olan, Oleg Prezhdo, and Valentina Zubkova. "Vapor-phase molar Kerr constant values from solution measurements." Wang, Linjun, Run Long, and Oleg V. Prezhdo. "Time-Domain Ab Initio Modeling of Photoinduced Dynamics at Nanoscale Interfaces." Wang, Linjun, Run Long, Dhara Trivedi, and Oleg V. Prezhdo. "Time-Domain Ab Initio Modeling of Charge and Exciton Dynamics in Nanomaterials." In Wang, Linjun, Oleg V. Prezhdo, and David Beljonne. "Mixed quantum-classical dynamics for charge transport in organics." Wang, Linjun, Andrew E. Sifain, and Oleg V. Prezhdo. "Fewest Switches Surface Hopping in Liouville Space." Sifain, Andrew E., Linjun Wang, and Oleg V. Prezhdo. "Mixed quantum-classical equilibrium in global flux surface hopping." Liu, Jin, Lyudmyla Adamska, Stephen K. Doorn, and Sergei Tretiak. "Singlet and triplet excitons and charge polarons in cycloparaphenylenes: a density functional theory study." Liu, Jin, Svetlana Kilina, Sergei Tretiak, and Oleg V. Prezhdo. "Ligands Slow Down Pure-Dephasing in Semiconductor Quantum Dots." Liu, Jin, and Oleg V. Prezhdo. "Chlorine Doping Reduces Electron–Hole Recombination in Lead Iodide Perovskites: Time-Domain Ab Initio Analysis." Trivedi, Dhara J., Linjun Wang, and Oleg V. Prezhdo. "Auger-Mediated Electron Relaxation Is Robust to Deep Hole Traps: Time-Domain Ab Initio Study of CdSe Quantum Dots." Trivedi, Dhara J., and Oleg V. Prezhdo. "Decoherence Allows Model Reduction in Nonadiabatic Dynamics Simulations." Long, Run, and Oleg V. Prezhdo. "Time-Domain Ab Initio Analysis of Excitation Dynamics in a Quantum Dot/Polymer Hybrid: Atomistic Description Rationalizes Experiment." Long, Run, and Oleg V. Prezhdo. "Dopants Control Electron-Hole Recombination at Perovskite-TiO2 Interfaces: Ab Initio Time-Domain Study." Neukirch, Amanda J., Jinhee Park, Vladmir Zobac, Hong Wang, Pavel Jelinek, Oleg V. Prezhdo, Hong-Cai Zhou, and James P. Lewis. "Calculated photo-isomerization efficiencies of functionalized azobenzene derivatives in solar energy materials: azo-functional organic linkers for porous coordinated polymers." Postupna, Olena, Run Long, and Oleg V. Prezhdo. "Time-Domain Ab Initio Simulation of Energy Transfer in Double-Walled Carbon Nanotubes." Chaban, Vitaly V., Eudes Eterno Fileti, and Oleg V. Prezhdo. "Buckybomb: Reactive Molecular Dynamics Simulation." Chaban, Vitaly V., and Oleg V. Prezhdo. "Nonadditivity of Temperature Dependent Interactions in Inorganic Ionic Clusters." Chaban, Vitaly V., and Oleg V. Prezhdo. "Are Fluorination and Chlorination of the Morpholinium-Based Ionic Liquids Favorable?." Chaban, Vitaly V., and Oleg V. Prezhdo. "Synergistic Amination of Graphene: Molecular Dynamics and Thermodynamics." Kamat, Prashant V., Benedetta Mennucci, Oleg Prezhdo, Gregory Scholes, Francisco Zaera, Timothy Zwier, and George C. Schatz. "A Prolific First Five Years." Tafen, De Nyago, and Oleg V. Prezhdo. "Size and Temperature Dependence of Electron Transfer between CdSe Quantum Dots and a TiO2 Nanobelt." Nie, Zhaogang, Run Long, Jefri Teguh, Chung-Che Huang, Daniel W. Hewak, Edwin KL Yeow, Zexiang Shen, Oleg V. Prezhdo, and Zhi-Heng Loh. "Ultrafast Electron and Hole Relaxation Pathways in Few-Layer MoS2." Sowers, Kelly L., Zhentao Hou, Jeffrey J. Peterson, Brett Swartz, Sougata Pal, Oleg Prezhdo, and Todd D. Krauss. "Photophysical Properties of CdSe/CdS core/shell Quantum Dots with Tunable Surface Composition." Zhou, Zhaohui, Pengju Huo, Liejin Guo, and Oleg V. Prezhdo. "Understanding Hematite Doping with Group Ⅳ Elements: A DFT+ U Study." Chen, Xue, Oleg V. Prezhdo, Zeyao Ma, Tingjun Hou, Zhenyu Guo, and Youyong Li. "Ab initio phonon‐coupled nonadiabatic relaxation dynamics of [Au25 (SH) 18]− clusters." Sowers, Kelly L., Zhentao Hou, Jeffrey J. Peterson, Brett Swartz, Sougata Pal, Oleg Prezhdo, and Todd D. Krauss. "Photophysical Properties of CdSe/CdS core/shell quantum dots with tunable surface composition." Dong, Shuo, Dhara Trivedi, Sabyasachi Chakrabortty, Takayoshi Kobayashi, Yinthai Chan, Oleg V. Prezhdo, and Zhi-Heng Loh. "Observation of an Excitonic Quantum Coherence in CdSe Nanocrystals." |