题目1：Extending the atomistic simulation timescales using Accelerated Molecular Dynamics
报告人：Dr. Danny Perez (Los Alamos National Laboratory, USA)
题目2：Computational modeling of actinides in the natural environment
报告人：Dr. Ping Yang (Pacific Northwest National Laboratory, USA)
Abstract1: Materials possess an extremely wide range of characteristic timescales. Though vibrational motion occurs over picoseconds, microseconds can be required for local conformational changes. Nanostructures globally evolve on even longer timescales, typically milliseconds or more. Many important phenomena are therefore totally inaccessible to direct simulation using molecular dynamics (MD), which is typically limited to microseconds or less. This rather severe limitation often makes correspondence between simulations and experiments difficult. In this talk, I will discuss recent developments in Accelerated Molecular Dynamics method, a set of techniques that allows the extension of the timescale of MD simulations. I will demonstrate that these techniques can be used to study a wide range of problems in materials physics that are not amenable to conventional approaches.
Abstract2: Actinides are of environmental and health concern due to their introduction into groundwater and the natural environment via nuclear activities. The complicated electronic structure of actinide complexes leads to their versatility of chemical reactivity, spectral and magnetic properties. It is critical to have a fundamental understanding of the electronic structures associated to actinides in homogeneous and heterogeneous environments. In this talk, we will show that computational chemistry modeling can be used as an effective tool to provide a first-principles description yielding insight into actinides-ligand bonding interactions, complimentary to modern experimental spectroscopic techniques. Our calculations provide insights into the physico-chemical properties of actinide complexes in the natural environment, a step towards rational design of therapies for removing toxic actinyl cations and remediation technologies for environmental contaminants.
Dr. Perez is a staff research scientist in the “Physics and Chemistry of Materials” group in the Theoretical Division at Los Alamos National Laboratory. His group’s research is focused on the computational study of the statistical mechanics underpinnings of kinetics and on the understanding of the atomistics of slow micro-structural evolution in materials. Prior to joining Los Alamos National Laboratory in 2007, first as a Director’s Fellow, then as a staff scientist, Dr. Perez obtained his M.Sc. and Ph.D. in Physics at the Universite de Montreal, in Canada, where he was primarily interested in the multiscale modeling of phase separation kinetics in alloys. During his graduate studies in Montreal, he was awarded two prestigious Academic Gold Medals of the Governor General of Canada.
Dr. Yang is a senior research scientist in the Molecular Science Computing group of the Environmental Molecular Science Laboratory at Pacific Northwest National Laboratory. Prior to joining Pacific Northwest National Laboratory in 2008, Dr Yang was a Seaborg Postdoctoral Fellow in the Theoretical Division at Los Alamos National Laboratory. Dr. Yang obtained a PhD in Chemistry and a Master in Computer Science from Michigan Tech. She graduated from Southeast University prior her abroad study. Her current research interests lie in computational chemistry in the area of bio--‐related and nano--‐materials containing transition metals and heavy elements.