Computational Characterizaion of Non-covalent Clusters with New and Existing Methods

在这个由化学系化学结构、动力学和机理A(CSDM-A)和大分子、超分子和纳米化学(MSN)计划资助的项目中，密西西比大学的Greg Tschumper教授正在使用基于量子力学(QM)的计算工具来模拟和研究通过弱相互作用聚集在一起的分子簇。正是弱相互作用导致原子和分子相互粘在一起，而不是真正形成化学键。弱相互作用包括氢键、卤素键和伦敦弥散力。这些计算补充了正在进行的实验研究，范围从溶剂化的基础研究到新分子、纳米级组件和材料的设计、合成和表征。更广泛地说，这项工作的影响包括加速开发具有潜在社会效益的新材料(例如，清洁能源、药物输送和紧凑型柔性电子产品)。这项研究计划对研究生和本科生中代表性不足的群体的理科学生的教育和培训产生了积极的影响。通过与中央阿拉巴马州社区学院(CACC)的Jeremy Carr教授的合作，Tschumper教授为社区学院的学生提供了研究经验。该项目分为两部分，第一部分使用基于密度泛函理论(DFT)和波函数理论(WFT)的校准方法进行一系列计算研究，以促进实验表征(光谱、结晶学等)。这些方法做出了可靠的预测，有助于设计和合成新的分子、纳米结构和材料。研究的第二个方面集中在N体：多体集成QM：QM方法的继续发展上，以使高精度的QM技术能够常规地应用于较大的非共价团簇，具有适度的计算资源，如经常在单个研究实验室或小部门中找到的那些。重点是用N体：多体框架内的系统收敛技术来评估非共价团簇的光谱性质(例如，非谐振动频率和核磁共振化学位移)，以及将该方法的准确性和效率扩展到包含开壳、离子和激发态物种的分子聚集体。

In this project funded by the Chemical Structure, Dynamics and Mechanisms-A (CSDM-A) and Macromolecular, Supramolecular and Nanochemistry (MSN) programs of the Division of Chemistry, Professor Greg Tschumper of the University of Mississippi is using computational tools based on quantum mechanics (QM) to model and study clusters of molecules held together by weak interactions. It is weak interactions that cause atoms and molecules stick to each other without actually forming chemical bonds. Weak interactions include hydrogen bonding, halogen bonding, and London dispersion forces. These computations complement ongoing experimental investigations ranging from fundamental studies of solvation to the design, synthesis and characterization of new molecules, nano-scale assemblies and materials. More broadly, the impact of this work includes accelerating the development of novel materials with potential societal benefits (e.g., clean energy, drug delivery, and compact flexible electronics). This research program has a positive impact on the education and training of science students from underrepresented groups at the graduate and undergraduate levels. Through a collaboration with Professor Jeremy Carr of Central Alabama Community College (CACC), Professor Tschumper provides research experiences for community college students.The project is divided into two parts, the first of which employs well-calibrated methods based on both density functional theory (DFT) and wave function theory (WFT) to a series of computational investigations devised to facilitate experimental characterization(spectroscopic, crystallographic, etc.). The methods make reliable predictions that can aid efforts to design and synthesize new molecules, nano-structures and materials. The second aspect of the research concentrates on the continued development of the N-body : Many-body integrated QM : QM methodology to enable the routine application of high-accuracy QM techniques to larger non-covalent clusters with modest computational resources like those often found in individual research labs or small departments. Emphasis is placed on evaluating spectroscopic properties (e.g.,anharmonic vibrational frequencies and NMR chemical shifts) of non-covalent clusters with systematically convergent techniques within the N-body : Many-body framework as well as extending the accuracy and efficiency of the approach to molecular aggregates containing open-shell, ionic and excited state species.