Quantum chemistry

In Silico Searches for Efficient Renewable Energy Catalysts Through Chemical Compound Space

Speaker(s): 
John Keith
Dates: 
Friday, February 3, 2017 - 11:30am to 12:30pm

This talk will provide an overview of our group’s work using both standard and atypical high-performance computational chemistry modeling to elucidate atomic scale reaction mechanisms of catalytic reactions. I will introduce our toolkit of in silico methods for accurately modeling solvating environments and realistic nanoscale architectures. I will then present how these methods can be used for predictive insights into chemical and material design. The talk will then summarize our progress in unraveling reaction mechanisms for 1) electrochemical CO2 reduction with...

Peng Liu Receives NSF CAREER Award

  • By Aude Marjolin
  • 16 December 2016

Peng Liu has been selected to receive a National Science Foundation CAREER award based upon his proposal, entitled "Computational Studies of Transition-Metal-Catalyzed Reactions in Organic Synthesis." 

In this CAREER project funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Peng Liu of the Department of Chemistry at the University of Pittsburgh is developing new strategies to use computational tools to investigate mechanisms and effects of ancillary ligands in transition-metal-catalyzed reactions of unactivated starting materials, such as C-C and C-H bonds, and unactivated olefins. The goal of this research is to reveal the fundamental reactivity rules of common organometallic intermediates in these transformations and to develop new models to interpret ligand effects on reactivity and selectivity. This proposal’s educational and outreach plan aims to maximize the power of computations to enhance learning of organic chemistry concepts and to facilitate synthetic organic chemistry research. Professor Liu’s team will develop virtual reality (VR) software and educational materials to visualize three-dimensional molecular structures and reaction mechanism videos in an interactive and immersive environment.

Snapshots of Proton Conduction Process in Water

  • By Aude Marjolin
  • 5 December 2016

Scientists Capture Snapshots of the Proton Conduction Process in Water

The motion of protons (positively charged H atoms) in water is associated with water’s conduction of electricity and is involved in many important processes including vision, signaling in biological systems, photosynthesis and, the operation of fuel cells. Both artificial photosynthetic systems and fuel cells are of growing interest for clean energy technologies. However, the details of how protons move in water have remained elusive, and an enhanced understanding of the nature of this process is needed to improve the technologies that depend on proton transfer.

An international team of scientists, including a University of Pittsburgh professor and graduate student, has used spectroscopic methods to obtain snapshots of the process by which a proton is relayed from one water molecule to the next. The research is published in a paper in the December 2, 2016 issue of the journal Science.

Structure and Reactivity of Functional Molecules on Surfaces

Speaker(s): 
Reinhard J. Maurer
Dates: 
Thursday, February 9, 2017 - 4:00pm to 5:00pm

Fundamental understanding of molecular structure and chemical reactivity at complex interfaces is key to many technological applications ranging from single molecule electronics to functional surfaces. An important goal of molecular nanotechnology is to manipulate single molecules in well-defined chemical environments. Using electronic structure methods, we study prototypical example systems such as azobenzene [1] and porphyrine [2] derivatives adsorbed on well-defined single crystal metal surfaces. Hereby the focus lies on the effects of molecule functionalization,...

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Personal | Department
Department of Mechanical Engineering, Carnegie Mellon University
Ph.D., Mechanical Engineering, Stanford University, 2013
Summary:

Venkat Viswanathan's research focus is on identifying the scientific principles governing material design, inorganic, organic and biomaterials, for novel energy conversion and storage routes. The material design is carried out through a suite of computational methods being developed in the group validated by experiments.  Some key research thrusts include identifying principles of electrolytes design (organic material) that can tune electrode catalysis, identification of new anode, cathode (inorganic materials) and electrolyte materials for next generation batteries, new electrocatalysts (inorganic) and biomaterials for energy storage and separation applications. In addition to material design, our group is involved in several cross-cutting areas such as battery controls, electric vehicle security and GPU accelerated computing.

Research interests:

  • Computational material design
  • Density functional theory simulations
  • Phase-field modeling
  • Next generation batteries, fuel cells
  • Electrocatalysis for energy conversion and storage
  • Data-driven material discovery
  • Bio-inspired and bio-mimetic materials
  • Controls for energy systems
  • GPU accelerated computing
Most Cited Publications: 
  1. "Twin Problems of Interfacial Carbonate Formation in Nonaqueous Li–O2 Batteries," B. D. McCloskey, A. Speidel, R. Scheffler, D. C. Miller, V. Viswanathan, J. S. Hummelshøj, J. K. Nørskov, and A. C. Luntz, J. Phys. Chem. Lett. 3, 997 (2012)
  2. "Electrical conductivity in Li2O2 and its role in determining capacity limitations in non-aqueous Li-O2 batteries," V. Viswanathan, K. S. Thygesen, J. S. Hummelshøj, J. K. Nørskov, G. Girishkumar, B. D. McCloskey and A. C. Luntz, J. Chem. Phys. 135, 214704 (2011)
  3. "Solvating additives drive solution-mediated electrochemistry and enhance toroid growth in non-aqueous Li–O2 batteries" Nagaphani B. Aetukuri, Bryan D. McCloskey, Jeannette M. García, Leslie E. Krupp, Venkatasubramanian Viswanathan & Alan C. Luntz, Nature Chemistry 7, 50 (2015)
  4. "Universality in Oxygen Reduction Electrocatalysis on Metal Surfaces," Venkatasubramanian Viswanathan, Heine Anton Hansen, Jan Rossmeisl, and Jens K. Nørskov, ACS Catal. 2, 1654 (2012)
  5. "Direct observation of the oxygenated species during oxygen reduction on a platinum fuel cell cathode," Hernan Sanchez Casalongue, Sarp Kaya, Venkatasubramanian Viswanathan, Daniel J. Miller, Daniel Friebel, Heine A. Hansen, Jens K. Nørskov, Anders Nilsson & Hirohito Ogasawara, Nature Communications 4, 2817 (2013)
Recent Publications: 
  1. "Effect of Dynamic Surface Polarization on the Oxidative Stability of Solvents in Nonaqueous Li-O2 Batteries," Abhishek Khetan, Heinz Pitsch, Venkatasubramanian ViswanathanarXiv:1705.03862
  2. "Synthesis and Measurement of Cohesive Mechanics in Polydopamine Nanomembranes," Luke Klosterman, Zeeshan Ahmad, Venkatasubramanian Viswanathan, Christopher J. Bettinger, Adv. Mater. Interfaces, 1700041 (2017)
  3. "Stability of electrodeposition at solid-solid interfaces and implications for metal anodes," Zeeshan Ahmad, Venkatasubramanian Viswanathan, arXiv:1702.08406
  4. "One- or Two-Electron Water Oxidation, Hydroxyl Radical, or H2O2 Evolution," Samira Siahrostami, Guo-Ling Li, Venkatasubramanian Viswanathan, and Jens K. Nørskov, J. Phys. Chem. Lett., 8, 1157 (2017)
  5. "The role of disorder in NaO2 and its implications for Na-O2 batteries," Oleg Sapunkov, Vikram Pande, Abhishek Khetan, Venkatasubramanian ViswanathanarXiv:1702.05520
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Personal | Department
Department of Physics and Astronomy, University of Pittsburgh
Ph.D. Physics, University of Science & Technology of China, 2003
Summary:

1. The wet electron structure of the H/H2O/TiO2(110) surfaces system using Density Functional Theory.

2. The excited state structure of H/H2O/TiO2(110) using delta-scf method and TDDFT.

3. The resonance of alkali atoms adsorbed on Ag and Cu surface using first-principle and model potential calculation methods.

Selected Publications: 
  • "Time-resolved photoemission study of the electronic structure and dynamics of chemisorbed alkali atoms on Ru(0001)," Shengmin Zhang, Cong Wang, Xuefeng Cui, Yanan Wang, Adam Argondizzo, Jin Zhao and Hrvoje Petek, Phys. Rev. B 93, 045401 (2016)
  • "Temperature- and Coverage-Dependent Kinetics of Photocatalytic Reaction of Methanol on TiO2(110)-(1x1) Surface," Hao Feng, Shijing Tan, Haoqi Tang, Qijing Zheng, Yongliang Shi, Xuefeng Cui, Xiang Shao, Aidi Zhao, Jin Zhao, and Bing Wang, J. Phys. Chem. C, 120, 5503 (2016)
  • "Nano-scale Polar-Nonpolar Oxide Heterostructures for Photocatalysis," Hongli Guo, Wissam A. Saidi, Jinlong Yang and Jin Zhao, Nanoscale 8, 6057 (2016)

Quantum Mechanics, Chemical Space, and Machine Learning

Speaker(s): 
O. Anatole von Lilienfeld
Dates: 
Thursday, September 29, 2016 - 4:30pm to 5:30pm

Many of the most relevant chemical properties of matter depend explicitly on atomistic details, rendering a first principles approach mandatory. Alas, even when using high-performance computers, brute force high throughput screening of compounds is beyond any capacity for all but the simplest systems and properties due to the combinatorial nature of chemical space, i.e. all compositional, constitutional, and conformational isomers. Consequently, efficient exploration algorithms need to exploit all implicit redundancies present in chemical space. I will discuss...

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Personal | Department
Department of Materials Science and Engineering, Carnegie Mellon University
Ph.D., Chemistry, Weizmann Institute of Science, 2010
Summary:

Computational Materials Science

The goal of our research is to computationally design materials with desired properties for target applications.

Through the portal of computer simulations we gain access to the vast configuration space of materials structure and composition. We can explore the uncharted territories of materials that have not been synthesized yet and predict their properties from first principles, based solely on the knowledge of their elemental composition and the laws of quantum mechanics.

To navigate the configuration space we use genetic algorithms, steered to the most promising regions by the evolutionary principle of survival of the fittest. We develop a massively parallel genetic algorithm code, GAtor, and run it on some of the world’s most powerful supercomputers. We apply our methods to study functional nano-structured interfaces in organic and hybrid solar cells, molecular crystals, layered materials, and cluster-based nanocatalysts.

Most Cited Publications: 
  1. "Dispersion Interactions with Density-Functional Theory: Benchmarking Semiempirical and Interatomic Pairwise Corrected Density Functionals," Noa Marom, Alexandre Tkatchenko, Mariana Rossi, Vivekanand V. Gobre, Oded Hod, Matthias Scheffler, and Leeor Kronik, J. Chem. Theory Comput. 7, 3944 (2011)
  2. "Stacking and Registry Effects in Layered Materials: The Case of Hexagonal Boron Nitride," Noa Marom, Jonathan Bernstein, Jonathan Garel, Alexandre Tkatchenko, Ernesto Joselevich, Leeor Kronik, and Oded Hod, Phys. Rev. Lett. 105, 046801 (2010)
  3. "Electronic structure of copper phthalocyanine: A comparative density functional theory study," Noa Marom, Oded Hod, Gustavo E. Scuseria, and Leeor Kronik, J. Chem. Phys. 128, 164107 (2008)
  4. "Describing Both Dispersion Interactions and Electronic Structure Using Density Functional Theory: The Case of Metal−Phthalocyanine Dimers," Noa Marom, Alexandre Tkatchenko, Matthias Scheffler and Leeor Kronik, J. Chem. Theory Comput. 6, 81 (2010)
  5. "Density functional theory of transition metal phthalocyanines, I: electronic structure of NiPc and CoPc—self-interaction effect," Noa Marom, Leeor Kronik, Appl. Phys. A 95, 159 (2009)
Recent Publications: 
  1. "Effect of packing motifs on the energy ranking and electronic properties of putative crystal structures of tricyano-1,4-dithiino[c]-isothiazole," F. Curtis, X. Wang and N. MaromActa Cryst. B72, 562 (2016)
  2. "Accurate Ionization Potentials and Electron Affinities of Acceptor Molecules IV: Electron-Propagator Methods," O. Dolgounitcheva, Manuel Díaz-Tinoco, V. G. Zakrzewski, Ryan M. Richard, Noa Marom, C. David Sherrill, and J. V. Ortiz J. Chem. Theory Comput. 12, 627 (2016)
  3. "Accurate Ionization Potentials and Electron Affinities of Acceptor Molecules III: A Benchmark of GW Methods," Joseph W. Knight, Xiaopeng Wang, Lukas Gallandi, Olga Dolgounitcheva, Xinguo Ren, J. Vincent Ortiz, Patrick Rinke, Thomas Körzdörfer, and Noa MaromJ. Chem. Theory Comput. 12, 615 (2016)
  4. "Accurate Ionization Potentials and Electron Affinities of Acceptor Molecules II: Non-Empirically Tuned Long-Range Corrected Hybrid Functionals," Lukas Gallandi, Noa Marom, Patrick Rinke, and Thomas Körzdörfer, J. Chem. Theory Comput. 12, 605 (2016)
  5. "Accurate Ionization Potentials and Electron Affinities of Acceptor Molecules I. Reference Data at the CCSD(T) Complete Basis Set Limit," Ryan M. Richard, Michael S. Marshall, O. Dolgounitcheva, J. V. Ortiz, Jean-Luc Brédas, Noa Marom, and C. David Sherrill, J. Chem. Theory Comput. 12, 595 (2016)
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Personal | Department
Department of Chemical and Petroleum Engineering, University of Pittsburgh
Ph.D., Theoretical and Computational Chemistry, University of Crete, 2006
Summary:

My research expertise is interdisciplinary, blending concepts and techniques from Chemistry, Physics, Materials Science and Chemical Engineering. I use theory and computation to investigate the physicochemical properties of nanomaterials with potential applications in diverse nanotechnological areas, ranging from energy generation and storage, to materials design, nanoparticle growth, magnetism, and catalysis.

In the Computer-Aided Nano and Energy Lab (C.A.N.E.LA.), led by Prof. Mpourmpakis, we use theory and computation to investigate the physicochemical properties of nanomaterials with potential applications in diverse nanotechnological areas, ranging from green energy generation and storage to materials engineering and catalysis. Our laboratory core expertise lies on "ab-initio" electronic-structure theoretical calculations. We develop structure-activity relationships and apply multiscale tools to elucidate complex chemical processes that take place on nanomaterials. Ultimately, we design novel nanostructures with increased, molecular-level precision and tailored multifunctionality. 

Most Cited Publications: 
  1. "SiC Nanotubes:  A Novel Material for Hydrogen Storage," Giannis Mpourmpakis and George E. Froudakis, George P. Lithoxoos and Jannis Samios, Nano Lett. 6, 1581 (2006)
  2. "Carbon Nanoscrolls:  A Promising Material for Hydrogen Storage," Giannis Mpourmpakis, Emmanuel Tylianakis, and George E. Froudakis, Nano Lett. 7, 1893 (2007)
  3. "Correlating Particle Size and Shape of Supported Ru/γ-Al2O3 Catalysts with NH3 Decomposition Activity," Ayman M. Karim, Vinay Prasad, Giannis Mpourmpakis, William W. Lonergan, Anatoly I. Frenkel, Jingguang G. Chen and Dionisios G. Vlachos, J. Am. Chem. Soc.131, 12230 (2009)
  4. "Stabilization of Si-based cage clusters and nanotubes by encapsulation of transition metal atoms," Antonis N Andriotis, Giannis Mpourmpakis, George E Froudakis2 and Madhu Menon, New J. Phys. 4, 78 (2002)
  5. "Why boron nitride nanotubes are preferable to carbon nanotubes for hydrogen storage?: An ab initio theoretical study," Giannis Mpourmpakis, George E. Froudakis, Catalysis Today 120, 341 (2007)
Recent Publications: 
  1. "CO2 activation on bimetallic CuNi nanoparticles," Natalie Austin, Brandon Butina, Giannis MpourmpakisProgress in Natural Science: Materials International 26, 487 (2016)
  2. "From Biomass-Derived Furans to Aromatics with Ethanol over Zeolite," Ivo F. Teixeira, Benedict T. W. Lo, Pavlo Kostetskyy, Michail Stamatakis, Lin Ye, Chiu C. Tang, Giannis Mpourmpakis, Shik Chi Edman Tsang, Angew. Chem. Int. Ed. 55, 13061 (2016)
  3. "Molecular modifiers reveal a mechanism of pathological crystal growth inhibition," Jihae Chung, Ignacio Granja, Michael G. Taylor, Giannis Mpourmpakis, John R. Asplin & Jeffrey D. Rimer, Nature 536, 446 (2016)
  4. "Description and Role of Bimetallic Prenucleation Species in the Formation of Small Nanoparticle Alloys," Lauren E. Marbella, Daniel M. Chevrier, Peter D. Tancini, Olabobola Shobayo, Ashley M. Smith, Kathryn A. Johnston, Christopher M. Andolina, Peng Zhang, Giannis Mpourmpakis, and Jill E. Millstone, J. Am. Chem. Soc. 137, 15852 (2015)
  5. "Catalyst Design Based on Morphology- and Environment-Dependent Adsorption on Metal Nanoparticles," Michael G. Taylor, Natalie Austin, Chrysanthos E. Gounaris, and Giannis MpourmpakisACS Catal. 5, 6296 (2015)
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Personal | Department
Department of Chemistry, University of Pittsburgh
Ph.D., Computational Organic Chemistry, University of California, 2010
Summary:

Reactivity and Selectivity Rules in Organic and Organometallic Reactions
We are developing computational models to quantitatively describe the origins of reactivity and selectivity in organocatalytic and transition metal-catalyzed reactions. We perform quantum mechanical calculations to explore the reaction mechanism, followed by thorough analysis on various stereoelectronic effects to predict how changes of the catalyst structure, substituents, and solvent affect rate and selectivity. We use quantitative energy decomposition methods to dissect the key interactions in the transition state and provide chemically meaningful interpretation to the computed reactivity and selectivity. We apply these computational studies to a broad range of organic and organometallic reactions, such as C–H and C–C bond activations, coupling reactions, olefin metathesis, and polymerization reactions. 

Catalyst Screening and Prediction
We are developing a multi-scale computational screening protocol which could efficiently rank the catalysts based on ligand-substrate interaction energies in the transition state. 

Applications of Computational Chemistry in Understanding Organic Chemistry
We are collaborating with experimental groups at Pitt and many other institutions to solve problems in organic chemistry using computational methods and programs. Our goal is to establish the most effective strategy to use modern computational methods and hardware to help address the grand challenges in synthetic chemistry. 

 

Most Cited Publications: 
  1. "Computational Studies of Ruthenium-Catalyzed Olefin Metathesis," Peng Liu, Buck LH Taylor, Jesus Garcia-Lopez, Kendall N Houk, Handbook of Metathesis, 2nd Edition, Volume 1: Catalyst Development and Mechanism (2015)
  2. "Computational Explorations of Mechanisms and Ligand-Directed Selectivities of Copper-Catalyzed Ullmann-Type Reactions," Gavin O. Jones, Peng Liu, K. N. Houk and Stephen L. Buchwald, J. Am. Chem. Soc. 132, 6205 (2010)
  3. "Suzuki−Miyaura Cross-Coupling of Aryl Carbamates and Sulfamates: Experimental and Computational Studies," Kyle W. Quasdorf, Aurora Antoft-Finch, Peng Liu, Amanda L. Silberstein, Anna Komaromi, Tom Blackburn, Stephen D. Ramgren, K. N. Houk, Victor Snieckus, and Neil K. Garg, J. Am. Chem. Soc. 133, 6352 (2011)
  4. "Z-Selectivity in Olefin Metathesis with Chelated Ru Catalysts: Computational Studies of Mechanism and Selectivity," Peng Liu, Xiufang Xu, Xiaofei Dong, Benjamin K. Keitz, Myles B. Herbert, Robert H. Grubbs, and K. N. Houk, J. Am. Chem. Soc. 134, 1464 (2012)
  5. "Palladium-Catalyzed Meta-Selective C–H Bond Activation with a Nitrile-Containing Template: Computational Study on Mechanism and Origins of Selectivity," Yun-Fang Yang, Gui-Juan Cheng, Peng Liu, Dasheng Leow, Tian-Yu Sun, Ping Chen, Xinhao Zhang, Jin-Quan Yu, Yun-Dong Wu, and K. N. Houk, J. Am. Chem. Soc. 136, 344 (2014)
Recent Publications: 
  1. "1,3-Dipolar Cycloaddition Reactions of Low-Valent Rhodium and Iridium Complexes with Arylnitrile N-Oxides," Ilke Ugur, Sesil Agopcan Cinar, Burcu Dedeoglu, Viktorya Aviyente, M. Frederick Hawthorne, Peng Liu, Fang Liu, K. N. Houk, and Gonzalo Jiménez-Osés, J. Org. Chem., Article ASAP
  2. "Synthesis of Boriranes by Double Hydroboration Reactions of N-Heterocyclic Carbene Boranes and Dimethyl Acetylenedicarboxylate," Timothy R. McFadden, Cheng Fang, Steven J. Geib, Everett Merling, Peng Liu, and Dennis P. Curran, J. Am. Chem. Soc. 139, 1726 (2017)
  3. "Benzazetidine synthesis via palladium-catalysed intramolecular C−H amination," Gang He, Gang Lu, Zhengwei Guo, Peng Liu & Gong Chen, Nature Chemistry 8, 1131 (2016)
  4. "Catalytic activation of carbon–carbon bonds in cyclopentanones," Ying Xia, Gang Lu, Peng Liu & Guangbin Dong, Nature 539, 546 (2016)
  5. "Photoredox-mediated Minisci C–H alkylation of N-heteroarenes using boronic acids and hypervalent iodine," Guo-Xing Li, Christian A. Morales-Rivera, Yaxin Wang, Fang Gao, Gang He, Peng Liu and Gong Chen, Chem. Sci. 7, 6407 (2016)

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