Development, implementation and application of the analytical calculation of energy derivatives, especially nuclear gradients, of electron-correlation methods employing wavefunctions that depend explictly on the interelectronic coordinates

使用明确依赖于电子间坐标的波函数的电子相关方法的能量导数（尤其是核梯度）的分析计算的开发、实施和应用

• 批准号: 5412724
• 负责人: Professor Dr. Willem M. Klopper
• 金额: --
• 依托单位: Abteilung für Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5412724?language=en
• 关键词: Development; implementation; application; analytical; calculation

The explicitly correlated approach in computational quantum chemistry comprises a family of methods using wavefunctions that depend explicitly on all electron-electron distances in the atom or molecule of interest. Today, functions of the interelectronic distances are utilized in various forms. They appear in linear or exponential (Gaussian) terms in the wavefunction, in similarity-transformed Hamiltonians and in the Jastrow functions of quantum Monte-Carlo calculations. All of these methods have the potential to compute the ground- and excited-state energies of a molecule with very high accuracy, without the need for an inacceptably large basis set of one electron orbitals. However, to the best of our knowledge, these accurate energies can only be computed in a prescribed and fixed nuclear configuration and none of the explicitly correlated methods can be used to compute analytically the first derivative of the energy with respect to nuclear displacements. It is the goal of the present project to develop and implement (for the first time) the analytical calculation of nuclear energy gradients at the level of second-order perturbation theory with terms linear in the interelectronic distances.

计算量子化学中的显式关联方法包括一系列使用波函数的方法，这些波函数明确地依赖于感兴趣的原子或分子中的所有电子-电子距离。今天，电子间距离的功能以各种形式使用。它们以线性或指数(高斯)项出现在波函数、相似变换的哈密顿量和量子蒙特卡罗计算的Jastrow函数中。所有这些方法都有可能以非常高的精度计算分子的基态和激发态能量，而不需要一个电子轨道的不可接受的大基组。然而，就我们所知，这些精确的能量只能在规定的和固定的核构型下计算，没有任何显式相关的方法可以用来解析地计算能量相对于核位移的一阶导数。本项目的目标是(首次)在二阶微扰理论水平上发展和实施具有电子间距离线性项的核能梯度的分析计算。