Density Functional Theory for van der Waals Interactions

描述(申请人提供)：Q-Chem是一个最先进的商业量子化学程序，用于对包括生物、化学和材料科学在内的广泛学科的原子和分子过程进行建模。在量子化学方法中，密度泛函理论(DFT)可能是应用最广泛的，特别是在分子生物学中，因为它能够以合理的计算代价精确地模拟广泛的分子体系。尽管如此，DFT不包括色散关联效应或van der Waals相互作用，后者在确定分子体系的整体构象方面起着关键作用，因此在DNA和蛋白质、分子识别、晶体堆积等研究中是必不可少的。我们建议在DFT框架内增加精确建模色散效应的能力。具体地说，我们将开发和实现一个最近提出的色散模型的自洽场(SCF)和梯度解，该模型已经被证明对于没有经验参数的R-6和更高阶项得到非常精确的色散系数，对于弱束缚系统和只有两个经验参数的阻尼项的相对构象能得到非常精确的结合能。目前，由于缺乏SCF算法和梯度算法，该模型只能用于计算分子能量，不能应用于实际研究。该模型的成功开发和实施将为实际的化学和生物问题带来更可靠的DFT解决方案。 公共卫生相关性：该项目旨在开发和实施一种非常准确的DFT方法。离散傅立叶变换是分子模拟的核心，在生物研究和药物开发中得到了广泛的应用。改进后的离散傅里叶变换将显著提高研究人员的工作质量，扩大离散傅里叶变换的应用范围。

DESCRIPTION (provided by applicant): Q-Chem is a state-of-the-art commercial quantum chemistry program that is used to model atomic and molecular processes over a wide range of disciplines, including biology, chemistry, and materials science. Among the quantum chemistry methods, density functional theory (DFT) is perhaps the most widely used, especially in molecular biology, due to its ability to accurately model a wide range of molecular systems with reasonable computational cost. Still, DFT does not include the dispersion correlation effect, or van der Waals interaction, which plays a critical role in the determination of the overall conformations of molecular systems and accordingly, is indispensable in the study of DNA and proteins, molecular recognition, the packing of crystals, etc. We propose to add the ability to accurately model dispersion effects within the DFT framework. Specifically, we will develop and implement self-consistent-field (SCF) and gradient solutions to a recently proposed dispersion model, which has been shown to yield very accurate dispersion coefficients for R-6 and higher order terms with no empirical parameters, and very accurate binding energies for weakly bound systems and relative conformation energies with a damping term of just two empirical parameters. Currently this model cannot be applied in practical studies because it can only be used to calculate molecular energies due to the lack of SCF and gradient algorithms. The successful development and implementation of the model will lead to much more reliable DFT solutions for real chemical and biological problems. PUBLIC HEALTH RELEVANCE: This project aims to develop and implement a very accurate DFT method. DFT is at the core of molecular modeling and is applied widely in biological research/development and in drug discovery. The improved DFT will significantly increase researchers' quality of work and extend the application scope of DFT.