AB INITIO CALCULATIONS OF VITAMIN B12 COMPOUNDS

维生素 B12 化合物的从头计算

• 批准号: 7956095
• 负责人: RONALD L BIRKE
• 金额: $ 0.08万
• 依托单位: CARNEGIE-MELLON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7956095
• 关键词: Biomedical Research; Cobalamin; Computer Retrieval of Information on Scientific Projects Database; Coupling; Electronics; Frequencies; Funding; Grant; High Performance Computing; Hybrids; Institution; Metals; Potential Energy; Process; Relative (related person); Research; Research Personnel; Resources; Source; Surface; System; United States National Institutes of Health; Vitamin B 12; base; dalton; electronic spectra; nanoparticle; programs; quantum chemistry

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We are developing computations of Raman frequencies and intensities for Ag-cluster-molecule systems and for substituted-cobalamin molecules where vibronic coupling is important. Also we are calculating electronic spectra and bond breaking processes in the substituted-cobalamin molecules. Our plan is to first calculated optimized ground states ( DFT) and excited states (TD-DFT) of cobalamin molecules and the Ag-cluster-molecule systems and to calculate their normal mode coordinates and frequencies, using the Gaussian or ADF package of quantum chemistry programs. We will use the LANL2DZ double zeta basis set at the B3LYP hybrid functional level and/or the BP86 functional with nonlocal correlation and the TZVP basis set. Relative activity of the modes will be compared to relative experimental intensity results. We will calculate and compare both static and dynamic polarizabilities. Then we will calculate resonant Raman intensities using either the ADF or the Dalton quantum chemistry program by taking numerical derivatives of the dynamic polarizability tensor components with respect to the normal mode displacements. For molecules on metal-clusters (nanoparticles) and for substituted-cobalamins, we will calculate excited state potential energy surfaces , dipole transition moments, and oscillator strengths. Finally the effect of vibonic coupling will be investigated by calculating the electronic coupling constants.

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们正在开发计算Ag-团簇-分子体系和取代钴胺分子的拉曼频率和强度，其中振动耦合是重要的。此外，我们还计算了取代钴胺分子的电子光谱和断键过程。我们的计划是首先计算钴胺分子和银团簇分子体系的优化基态(DFT)和激发态(TD-DFT)，并计算它们的简正模坐标和频率。我们将在B3LYP混合泛函水平上使用LANL2DZ双Zeta基组和/或具有非局部相关的BP86泛函和TZVP基组。模式的相对活度将与相对实验强度结果进行比较。我们将计算和比较静态和动态极化率。然后，我们将使用ADF或Dalton量子化学程序，通过取动态极化率张量分量相对于简正模位移的数值导数来计算共振拉曼强度。对于金属团簇(纳米颗粒)上的分子和取代钴胺分子，我们将计算激发态势能面、偶极跃迁矩和振子强度。最后，通过计算电子耦合常数来研究振子耦合的影响。