Ab initio method development for mechanistic studies of charge transport

南加州大学的安娜克雷洛夫得到了理论、模型和计算方法项目的一个奖项的支持，以开发预测性从头算方法来表征模型系统中电离态和电子附着态的电子结构，例如小的核碱基簇、DNA发夹或类似系统。 基于电离势和电子附着体系的运动方程耦合团簇方法（EOM-IP和EOM-EA），该方法能够以精确、稳健和高效的计算方案描述多个紧密排列的电子态 主要研究员及其研究小组正在（i）使用冻结自然轨道（FNO）方法实现EOM-IP-CCSD的性质和分析梯度计算;（ii）对IP-CCSD和IP-CISD方法实施非迭代三重校正，以提高这些方法的准确性;（iii）将FNO方案扩展到EOM-EA-CCSD能量和梯度计算; ㈣对戴森轨道和其他状态间性质进行有效计算，以帮助解释结果，并促进与实验进行更直接的比较;和（v）并行化和重新设计张量库，以利用现代计算机体系结构。Krylov小组开发的方法旨在研究通过分子导线的电荷传输，这在许多重要过程中起着核心作用，如DNA的辐射或氧化损伤，光捕获，分子电子学和太阳能应用。由该研究小组开发的软件通过在广泛使用的软件包中实现而提供给社区：Q-CHEM和SPARTAN。该奖项部分由与网络基础设施办公室（OCI）的共同资助安排支持。

Anna Krylov of the University of Southern California is supported by an award from the Theory, Models and Computational Methods program to develop predictive ab initio methods to characterize the electronic structure of ionized and electron-attached states in model systems, such as small clusters of nucleobases, DNA hairpins or similar systems. The proposed developments are based on the equation-of-motion coupled-cluster approach for ionization potentials (EOM-IP) and electron-attached (EOM-EA) systems, which is capable of describing multiple closely lying electronic states in an accurate, robust and efficient computational scheme The PI and her research group are (i) implementing properties and analytic gradient calculations for EOM-IP-CCSD using a Frozen Natural Orbitals (FNO) approach); (ii) implementing non-iterative triples corrections for the IP-CCSD and IP-CISD methods to improve accuracy of these methods; (iii) extending the FNO scheme to EOM-EA-CCSD energies and gradient calculations; (iv) implementing efficient calculations of Dyson orbitals and other inter-state properties to aid interpretation of the results and facilitate more direct comparisons with the experiments; and (v) parallelizing and redesigning the tensor library to take advantage of modern computer architecture.The Krylov group develops methods with the aim to study charge transport through molecular wires, which plays a central role in many important processes such as the radiative or oxidative damage in DNA, light harvesting, molecular electronics and solar energy applications. Software developed by this research group is made available to the community by being implemented in widely used software packages: Q-CHEM and SPARTAN.This award is supported partially by a co-funding arrangement with the Office of Cyberinfrastructure (OCI).