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Nonlinear Spectroscopy and Magnetic Circulardichroism with the Approximate Coupled-Cluster Singles-and-Doubles Method RI-CC2

使用近似耦合簇单双峰法 RI-CC2 进行非线性光谱和磁圆二色性分析

基本信息

批准号：
188802451
负责人：
Professor Dr. Christof Hättig
金额：
--
依托单位：
Lehrstuhl für Theoretische Chemie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/188802451?language=en
关键词：
Nonlinear Spectroscopy Magnetic Circulardichroism Approximate

项目摘要

In a second funding period the implementation of perturbation-induced transition moments for RI-CC2, developed in the first period, should be extended in two directions:firstly towards transition moments induced by magnetic fields, to describe magnetic circular dichroism (MCD), and secondly towards transitions between two excited states including spin-orbit couplingfor transitions between singlet and triplet states.MCD spectroscopy is experimentally often applied to obtain additional information which complements the results form UV/Vis absorption spectra since bands which overlap in the absorption spectrum can have opposite signs in the MCD spectrum. For closed-shell organic molecules the MCD spectrum is dominated by the so-called B term which describes a change in the oscillator strengths induced by the magnetic field. Despite the experimental importance of MCD spectroscopy theoretical computations of the MCD spectra of organic molecules are currently limited to density functional theory, which has knowndefiencies for charge-transfer and Rydberg excitations, or at correlated wavefunction levels to rather small molecules.An efficient implementation of MCD spectra for the approximate coupled-cluster singles-and-doubles model CC2 with the resolution-of-the-identity approximation (RI-CC2) would greatly extend the possibilities for theoretical studies of MCD at a correlated wavefunction level.

在第二个供资期内，第一个供资期内开发的RI-CC 2扰动诱导转捩力矩的实施应在两个方向上扩展：首先是磁场诱导的跃迁矩，用来描述磁性圆二色性（MCD），其次是两个激发态之间的跃迁，包括单重态和三重态之间的自旋-轨道耦合跃迁。MCD光谱在实验上经常被用来获得补充UV/MS结果的额外信息。维斯吸收光谱，因为在吸收光谱中重叠的谱带在MCD光谱中可能具有相反的符号。对于闭壳层有机分子，MCD谱由所谓的B项支配，该项描述了由磁场引起的振子强度的变化。尽管MCD光谱的实验重要性，但有机分子MCD光谱的理论计算目前仅限于密度泛函理论，该理论对电荷转移和Rydberg激发具有已知的缺陷，或在相关波函数水平上对相当小的分子进行。近似耦合簇单双模型CC 2的MCD谱的有效实现与单位分辨率近似（RI-CC 2）将大大扩展在相关波函数水平上对MCD进行理论研究的可能性。