Calculation of zero-field splitting parameters by density functional theory and ab-initio methods

密度泛函理论和从头算法计算零场分裂参数

• 批准号: 43475913
• 负责人: Professor Dr. Frank Neese
• 金额: --
• 依托单位: Max-Planck-Institut für Kohlenforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/43475913?language=en
• 关键词: Calculation; zero; field; splitting; parameters

The spectroscopic analysis of the excited triplet states plays an important role in diverse research fields. In particular, studying such states is essential for understanding the structure and reactivity of many important biological systems. Theoretical treatments can contribute to this research in various directions: (1) Calculation of the structure and energy surfaces of electronically excited states. (2) Qualitative analysis of the electronic structure of excited states. (3) Calculation of spectroscopic properties of excited triplet states, for (a) testing the quality of the calculated wave function or rather the electron and spin densities, and (b) the interpretation of the complex experimental spectra.This proposal is aimed at the calculation of the magnetic properties of the excited triplet states on the basis of Hartree-Fock (HF) and density functional theory (DFT) as well as correlated ab initio approaches. One of the important accessible parameters from EPR experiments is the zerofield splitting tensor, which describes the splitting of the MS= 0, ±1 components of the S = 1 state in zero applied magnetic field. Reliable quantum chemical methods and programs for the calculation of ZFS parameters for large systems are still scarce. A generally applicable program for the calculation of such properties will be developed and tested. Tasks to be completed include:1. Development and implementation of a resolution of identity (or density fitting) technique to speed up calculations of the spin-spin interaction for large systems;2. Implementation of a fully variational treatment that simultaneously accounts for the spin-spin and spin-orbit interactions on the complete active space self-consistent field ab initio level;3. Validation of the newly implemented methods;4. Application to biologically relevant systems.

激发三重态的光谱分析在不同的研究领域中起着重要的作用。特别是，研究这些状态对于理解许多重要生物系统的结构和反应性至关重要。理论处理可以在多个方向上对这一研究作出贡献：（1）电子激发态的结构和能量面的计算。(2)激发态电子结构的定性分析。(3)计算激发三重态的光谱性质，用于（a）测试计算的波函数的质量，或者更确切地说，测试电子和自旋密度，（B）对复杂实验谱的解释，本方案旨在基于Hartree-Fock（HF）和密度泛函理论（DFT）计算激发三重态的磁性以及相关的从头算方法。零场分裂张量是EPR实验中可获得的重要参数之一，它描述了S = 1态的MS= 0，±1分量在零外加磁场下的分裂。可靠的量子化学方法和程序的计算大系统的量子化学参数仍然是稀缺的。将开发和测试用于计算这些特性的普遍适用的程序。要完成的任务包括：1.开发和实施一种分辨同一性（或密度拟合）技术，以加快大型系统自旋-自旋相互作用的计算;2.实现了一个完全变分的处理，同时考虑自旋-自旋和自旋-轨道相互作用的完整的活性空间自洽场从头算水平;3。对新实施的方法进行验证;4.应用于生物相关系统。