研究领域

Computational/Theoretical Chemistry Organic Chemistry Physical Chemistry

Alternative energy research can greatly benefit from ab initio simulation that provides molecular level insight into the nature of chemical bonds and excited states. The level of detail found using these methods is extremely high and not often attainable via other means. However, many first principles methods are too costly for routine use in realistic systems due to poor scaling with system size. To alleviate this problem, our research group develops and applies state-of-the-art first-principles methods and support tools for the description of molecular catalysts and solar energy conversion systems. Discovering mechanisms of catalysis to guide experiments toward increased rates and selectivity. New methods are being developed in the group to navigate complex reaction pathways with minimal computational and human effort. These tools (one example is the Freezing String Method, see Selected Publications below) allow the study and discovery of catalytic processes even with limited a priori chemical insight. These methods are applied to difficult energy-related problems such as CO2 reduction and methane conversion. This approach identifies the strengths and limitations of existing catalysts at an atomistic level to aid in the design of improved catalytic systems. Characterizing the fundamental behavior of excited states in light harvesting materials. Solar cells and photocatalysts may be tuned to substantially higher efficiency when the character and interactions among electronically excited states are known. This level of detail, however, is especially hard to obtain due to the high cost of existing electronic structure methods that can treat excited states. New methods (such as Restricted Active Space Spin Flip) allow investigation of single and multiple exciton states in realistic models of molecular light harvesters and photocatalysts. The mechanistic information gained from these studies will lead to the development of highly efficient solar materials such as those that employ singlet fission, where a single photon is converted into two electron-hole pairs.

近期论文

查看导师新发文章 （温馨提示：请注意重名现象，建议点开原文通过作者单位确认）

P. M. Zimmerman, “Single-Ended Transition State Finding with the Growing String Method,” Journal of Computational Chemistry, published online: Link. Z. Sun, G. A. Winschel, P. M. Zimmerman, P. Nagorny, “Enantioselective Synthesis of Piperidines through the Formation of Chiral Mixed Phosphoric Acid Acetals: Experimental and Theoretical Studies,” Angewandte Chemie International Edition, 53, 11194-11198 (2014) Link. Highlighted in SYNFACTS October 2014: Link. P. M. Zimmerman, “Navigating Molecular Space for Reaction Mechanisms: An Efficient, Automated Procedure,” Molecular Simulation, Special Issue: “Recent Advances in the Molecular Simulation of Chemical Reactions” DOI: 10.1080/08927022.2014.894999 (2014). P. M. Zimmerman, “Reliable Transition State Searches Integrated with the Growing String Method,” Journal of Chemical Theory and Computation, 9, 3043-3050 (2013). S. M. Sharada, P. M. Zimmerman, M. Head-Gordon, A. T. Bell, “Insights into the kinetics of cracking and dehydrogenation reactions of light alkanes in H-MFI,” Journal of Physical Chemistry 117(24), 12600-12611 (2013). P. M. Zimmerman, “Growing string method with interpolation and optimization in internal coordinates: Method and examples,” Journal of Chemical Physics, 138, 184102 (2013). P. M. Zimmerman, “Automated Discovery of Chemically Reasonable Elementary Reaction Steps,” Journal of Computational Chemistry, 34(16), 1385, (2013). S. M. Sharada, P. M. Zimmerman, A. T. Bell, M. Head-Gordon, “Automated Transition State Searches without Evaluating the Hessian,” Journal of Chemical Theory and Computation, 8(12), 5166, (2012). P. M. Zimmerman, C. B. Musgrave, M. Head-Gordon, “A Correlated Electron View of Singlet Fission,” invited article Accounts of Chemical Research special issue: “Solar Energy Conversion with Multiple Excitons,” published online: DOI: 10.1021/ar3001734 (2013). P. M. Zimmerman, D. Tranca, J. Gomes, D. Lambrecht, A. T. Bell, M. Head-Gordon, “Ab Initio Simulations Reveal that Reaction Dynamics Strongly Affect Product Selectivity for the Cracking of Alkanes over H-MFI,” Journal of the American Chemical Society, 134, 19468-19476 (2012). F. Bell, P. M. Zimmerman, M. Goldey, M. Head-Gordon, “Restricted Active Space Spin-Flip (RAS-SF) with Arbitrary Number of Spin-Flips,” Physical Chemistry Chemical Physics, 15(1), 358-366 (2012). P. M. Zimmerman, F. Bell, M. Goldey, A. T. Bell, M. Head-Gordon, “Restricted Active Space n-Spin-Flip Configuration Interaction: Theory and Examples from Systems with Odd Numbers of Electrons,” Journal of Chemical Physics, 137(16), 164110 (2012). J. Gomes, P. M. Zimmerman, M. Head-Gordon, A. T. Bell, “Accurate Prediction of Hydrocarbon Interactions with Zeolites Utilizing Improved Exchange-Correlation Functionals and QM/MM Methods: Benchmark Calculations of Adsorption Enthalpies and Application to Ethene Methylation by Methanol,” Journal of Physical Chemistry C, 116, 15406-15414 (2012). A. Mlinar, P. M. Zimmerman, F. E. Celik, M. Head-Gordon, A. T. Bell, “Effects of Br?nsted Acid Site Proximity on the Oligomerization of Propene in H-MFI,” Journal of Catalysis, 288, 65-73 (2012). A. Behn, P. M. Zimmerman, A. T. Bell, M. Head-Gordon, “Incorporating Linear Synchronous Transit Interpolation into the Growing String Method: Algorithm and Applications,” Journal of Chemical Theory and Computation, 7(12) 4019-4025 (2011). A. Behn, P. M. Zimmerman, A. T. Bell, M. Head-Gordon, “Efficient exploration of reaction paths via a freezing string method,” Journal of Chemical Physics, 135, 224108 (2011). P. M. Zimmerman, F. Bell, D. Casanova, M. Head-Gordon, “Mechanism for singlet fission in tetracene and pentacene: from single exciton to two triplets,” Journal of the American Chemical Society, 133, 19944-19952 (2011). D. Stück, T. A. Baker, P. M. Zimmerman, W. Kurlancheek, M. Head-Gordon, “On the Nature of Electron Correlation in C60,” Journal of Chemical Physics, 135, 194306 (2011). P. M. Zimmerman, M. Head-Gordon, A. T. Bell, “Selection and validation of charge and Lennard-Jones parameters for QM/MM simulations of hydrocarbon interactions with zeolites,” Journal of Chemical Theory and Computation, 7(6), 1695-1703 (2011). P. M. Zimmerman, Z. Zhang, and C. B. Musgrave, “The dynamic mechanisms for ammonia borane thermolysis in solvent: deviation from gas phase minimum energy pathways,” Journal of Physical Chemistry Letters, 2, 276-281 (2011).