Development of a linear-scaling MP2 method for large molecules by rigorous integral criteria

通过严格的积分标准开发大分子线性缩放 MP2 方法

• 批准号: 16501951
• 负责人: Professor Dr. Christian Ochsenfeld
• 金额: --
• 依托单位: Department Chemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/16501951?language=en
• 关键词: Development; linear; scaling; MP2; method

Electron-correlation and in particular dispersion-type effects are crucial for the quantum-chemical calculation of many molecular systems. However, the computational effort of even the simplest ab initio approach accounting for these effects —second-order Møller-Plesset perturbation theory (MP2) — scales with the fifth power of molecular size, which prohibits the application of conventional approaches to more than 50–100 atoms. Therefore, the reduction of the scaling is crucial. Although impressive progress has been made by several groups towards this goal, there has been so far no rigorous way of preselecting numerically significant contributions to the correlation energy, so that either ad-hoc assumptions influencing the accuracy were necessary or the prefactors of the computational effort have been too large. In our work, we have introduced the first rigorous upper bounds (multipole-based integral estimates; MBIE) which allow to preselect the significant contributions to the MP2 energy without further assumptions. In this way, the same accuracy and reliability as in conventional approaches is guaranteed, combined with the possibility to attain a linear-scaling computational behavior. Based on this idea, the main goal of the present research proposal is the development of a linear-scaling MP2 method, which allows for the reliable computation of MP2 energetics for molecules with 500-1000 and more atoms (without symmetry), so that dispersion-type interactions can be accounted for in large molecular systems.

电子相关效应，特别是色散型效应，对于许多分子体系的量子化学计算是至关重要的。然而，即使是考虑到这些效应的最简单的从头算方法--二阶莫勒-普莱塞微扰理论(MP2)--的计算工作量也是分子大小的5次方，这阻止了传统方法应用于50-100个以上的原子。因此，减少结垢是至关重要的。尽管几个小组在实现这一目标方面取得了令人印象深刻的进展，但到目前为止还没有严格的方法来预先选择对关联能量有重大贡献的数字，因此要么是影响精度的临时假设是必要的，要么是计算工作量的前置因素太大。在我们的工作中，我们引入了第一个严格的上界(基于多极的积分估计；MBIE)，它允许预先选择对MP2能量的重要贡献，而不需要进一步的假设。通过这种方式，保证了与传统方法相同的精度和可靠性，并有可能实现线性缩放计算行为。基于这一思想，本研究方案的主要目标是发展一种线性标度MP2方法，该方法允许可靠地计算具有500-1000个或更多原子(无对称性)的分子的MP2能级，从而能够在大分子体系中解释色散型相互作用。