讲座题目：Beyond Structure - Multiscale Modeling of Chemical and Biophysical Processes in Complex Environments
主 讲 人：Dennis Salahub 院士
讲座内容简介：We are attempting to develop a multiscale, multimethodology approach to the computational modeling of chemical reactions in complex environments using High Performance Computational resources. Our main methods are Density Functional Theory (DFT), Density Functional Tight Binding (DFTB), Quantum Mechanical/ Molecular Mechanical (QM/MM) methods for both DFT and DFTB and the ReaxFF reactive force-field. The paradigm for the field is shifting from structure and potential-energy surfaces to dynamics and free-energy, incorporating polarizable environments.
I will report progress on some of the following applications in the areas of biomolecular modeling, nano-catalysis for oil sands upgrading, and earth science – humic and fulvic substances.
1.Biomolecular modeling: Great strides have been made in QM/MM methodologies, including those that utilize our deMon2k DFT software. Examples that have yielded mechanistic insight include enzymatic catalysis (RNA Polymerase), ions in protein channels, electron transfer between proteins and ultrafast electron dynamics in polarizable protein environments.
2.Nano-catalysis for oil sands upgrading: We have recently completed the first multiscale study of the hydrogenation of benzene by molybdenum carbide nanoparticles in a hydrocarbon MM environment including the important anharmonic entropic effects that contribute greatly to the free-energy profile. A next step may be the incorporation of a silaceous (sand) component. We have recently embarked on a similar exploration of Ni-ceria catalysts for the water gas shift reaction. To date we have performed periodic DFT (VASP) calculations for the three important (100), (111) and (110) surfaces of ceria with Ni present either as an adsorbate or as a substitutional dopant. The behavior of oxygen vacancies in relation to the formation of Ce3+ has been elucidated. These DFT calculations are being used in the parameterization of DFTB.
3.Humic and fulvic substances. We are using ReaxFF to study the chemistry of important earth science models. Complex organic mixtures along with metal ions evolve reactively yielding information on the dynamics of molecular units interacting with contaminants.
报告人简介：卡尔加里大学(University of Calgary)是加拿大知名的研究型大学。Dennis Salahub(丹尼斯.萨拉哈) 是加拿大皇家科学院院士，先后担任过加拿大蒙特利尔大学教授和加拿大分子与表面动力学跨校研究重点中心总协调人（Centers of Excellence on Molecular and Interfacial Dynamics），加拿大国家Steacie 分子科学研究所所长，卡尔加里大学负责科研的副校长。他是一位国际一流的理论与计算化学家。在过去的40 年里，他的研究小组在从量子化学的方法，及其在复杂性日益增加的体系中的应用等领域做出了杰出的贡献。他同时领导了deMon 跨越全球的研究开发网络。世界上几十位科学家参与此项目。每年都召开着眼于解决实际问题的研讨会。