A5071054345- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Amino Acid Enzymes and Metabolism
- Mass Spectrometry Techniques and Applications
- Quantum, superfluid, helium dynamics
- DNA and Nucleic Acid Chemistry
- Enzyme Structure and Function
- Cold Atom Physics and Bose-Einstein Condensates
- Molecular Junctions and Nanostructures
- Surface Chemistry and Catalysis
- Work-Family Balance Challenges
- Spectroscopy and Laser Applications
- Architecture, Design, and Social History
- Hemoglobin structure and function
- Quantum Mechanics and Applications
- Protein Structure and Dynamics
- Electron Spin Resonance Studies
- Atomic and Subatomic Physics Research
- Catalytic Processes in Materials Science
- History and advancements in chemistry
- Radical Photochemical Reactions
University of Cambridge
2014-2021
University of Stuttgart
2011-2014
We implemented and compared four algorithms to locate instantons, i.e., the most likely tunneling paths at a given temperature. These allow calculate reaction rates, including atom tunneling, down very low An instanton is first-order saddle point of Euclidean action in space closed Feynman paths. Newton-Raphson method partitioned rational function optimization (P-RFO) algorithm, dimer method, newly proposed mode-following where unstable mode directly estimated from path. tested on three...
The instanton method allows to accurately calculate tunneling rates down very low temperature. However, with lowering the temperature, computational effort steeply increases as many more discretization points are required. This is caused in practical applications by majority of accumulating at a small region configuration space. Here, we describe flexibly discretize path adapted Chosen appropriately, leads much uniform distribution images (control points) along which reduces number required...
The instanton method obtains approximate tunneling rates from the minimum-action path (known as instanton) linking reactants to products at a given temperature. An efficient way find is search for saddle-points on ring-polymer potential surface, which obtained by expressing quantum Boltzmann operator discrete path-integral. Here we report practical implementation of this form theory into Molpro electronic-structure package, allows be computed on-the-fly, without need fitted analytic...
The role of quantum mechanical atom tunneling during the conversion glutamate to methylaspartate catalyzed by mutase is investigated mechanical/molecular (QM/MM) simulations based on coupled cluster and density functional calculations. use instanton theory allows us calculate contributions up 78 atoms in active site. We kinetic isotope effects (KIEs) compare them experimental data. lead deuterium KIEs 10 for hydrogen abstraction from substrate 16 substrate, which are consistent with results....
We obtain a shallow-tunnelling correction factor for use with Wigner–Eyring transition-state theory (TST).
The ring-opening reaction of the cyclopropylcarbinyl radical proceeds via heavy-atom tunneling at low temperature. We used instanton theory to calculate rates and kinetic isotope effects with on-the-fly calculation energies by density functional (B3LYP). accuracy was verified explicitly correlated coupled-cluster calculations (UCCSD(T)-F12). At cryogenic temperatures, we found protium/deuterium KIEs up 13 inverse down 0.2. also studied an intramolecular tautomerization reaction. A simple...
The radical mechanism of the conversion glutamate to methylaspartate catalyzed by mutase is studied with quantum mechanical/molecular mechanical (QM/MM) simulations based on density functional theory (DFT/MM). hydrogen transfer between substrate and cofactor found be rate limiting a barrier 101.1 kJ mol–1. A careful comparison uncatalyzed reaction in water performed. protein influences predominantly electrostatically lesser degree sterically. Our calculations shed light atomistic details...
Peptidylglycine α-hydroxylating monooxygenase is a noninteracting bicopper enzyme that stereospecifically hydroxylates the terminal glycine of small peptides for its later amidation. Neuroendocrine messengers, such as oxytocin, rely on biological activity this enzyme. Each catalytic turnover requires one oxygen molecule, two protons from solvent, and electrons. Despite having been widely studied, consensus reaction mechanism has not yet found. Experiments theoretical studies favor pro-S...
Nanofabrication and the growth of self-assembled monolayers (SAM) organic molecules are increasingly important in various industries, including microelectronics health care. Glycine adsorbed on Cu{110} provides a good model with rich phenomenological space to explore understand self-assembly more complex amino acids. Our focus is (a) dynamics exhibited by glycine already when diffusing metal surface (b) chemical kinetics how these form clusters, networks, islands. The stochastic discrete...
Reliable predictions of the behaviour chemical systems are essential across many industries, from nanoscale engineering over validation advanced materials to nanotoxicity assessment in health and medicine. For future we therefore envision a paradigm shift for design simulations all length scales prescriptive predictive quantitative science. This paper presents an integrative perspective about state-of-the-art modelling computational theoretical chemistry with examples data- equation-based...
Julie Anson, Judy Brenholt, Bruce Cunningham, Anne Frantz-Cook, Sandra Gill, Bette Hanson, Jan Hare, Herr, Priscilla Huffman, Jax, Candace Jordan, Keil, Leslie Koepke, Yvonne Libby, Marian Marion, Judith Rommel, Robert Salt, Denise Skinner, Nancy Van Beest, John Williams, and Karen Zimmerman** The 1990 annual National Council on Family Relations (NCFR) Media Competition was hosted by the Human Development, Living Community Educational Services Department, University of Wisconsin-Stout,...