CAREER: Structure Prediction and Design of Molecular Crystals with the GAtor Genetic Algorithm Package

材料研究部和先进网络基础设施部为该奖项提供资金。它支持计算研究、算法开发和预测分子晶体性质的教育。分子晶体用于许多技术应用，包括有机电子学，太阳能电池和非线性光学。它们对制药业特别重要，因为大多数药物都是作为药物活性成分的分子晶体销售的。分子晶体是由分子间的范德华相互作用维系在一起的。与化学键不同，范德华相互作用是由电子密度的量子力学波动引起的，这种波动会产生微弱但具有长期吸引力的静电力。因为范德华相互作用很弱，一个给定的分子可能结晶成不止一种结构。不同的晶体结构可能导致分子晶体具有明显不同的物理和化学性质，几乎都是最受欢迎的结构。需要精确的计算来预测这次比赛的获胜者的结构，并能够设计新的分子晶体。通过计算机模拟的门户，PI将进入材料结构和组成的广阔构型空间。她将探索尚未合成的分子晶体的未知领域，并仅知道它们的元素组成和量子力学定律来预测它们的性质。通过这种方式，有希望的候选分子晶体的特定应用可以确定和用于指导合成工作。遗传算法（GAs）是通过计算机模拟实现“适者生存”的进化原则，引导到最有希望的配置。结合种群中最适合结构的结构“基因”，产生具有理想特征的“后代”，而采用随机突变来保持多样性。这种方法是在GA软件包GAtor中实现的，用于可以同时执行许多操作的计算机。PI将向更广泛的社区分发GAtor软件包。该奖项还支持教育活动。教育计划的目标是：(i)传授特定学科的知识和技术技能；（ii）发展科学和工程的基本技能，如解决问题、批判性思维和计算思维；（iii）灌输专业技能，如文献研究、科学写作和演讲技巧；（四）为学生的职业生涯做好准备；（五）扩大妇女和代表性不足的少数民族的参与。这将通过研究指导、研究生和本科课程的教学以及“物理和工程领域的女性领导者”系列研讨会来实现。技术摘要材料研究部和先进网络基础设施部为该奖项提供资金。它支持计算研究、算法开发和分子晶体教育。提出的研究目标是基于第一性原理的分子晶体的计算结构预测和设计。这将通过开发一种多功能遗传算法（GA）包GAtor来实现，GAtor能够以高精度和高效率进行基于能量和基于性能的优化。研究计划包括两个阶段：(I)结构预测阶段寻求预测分子晶体最稳定的结构，给出一个单分子的“棒图”——这是晶体结构预测盲测所体现的一个巨大挑战；（II）基于第一原理的晶体工程阶段寻求通过基于属性的GAs（计算材料设计中的新兴范例）设计具有目标特性的分子晶体，用于有机电子和光伏应用。PI将使用基于密度泛函理论的模拟，包括色散，以准确描述范德华相互作用产生的势能景观。多体微扰理论方法将用于精确描述激子性质。教育部分的目的是：(i)传授特定学科的知识和技术技能；（ii）发展科学和工程的基本技能，如解决问题、批判性思维和计算思维；（iii）灌输专业技能，如文献研究、科学写作和演讲技巧；（四）为学生的职业生涯做好准备；（五）扩大妇女和代表性不足的少数民族的参与。这将通过研究指导、研究生和本科课程的教学以及“物理和工程领域的女性领导者”系列研讨会来实现。

NONTECHNICAL SUMMARYThe Division of Materials Research and the Division of Advanced Cyberinfrastructure contribute funds to this award. It supports computational research, algorithm development, and education on predicting properties of molecular crystals. Molecular crystals are used for many technological applications, including organic electronics, solar cells, and non-linear optics. They are of particular importance to the pharmaceutical industry because most drugs are marketed as molecular crystals of the pharmaceutically active ingredient. Molecular crystals are held together by van der Waals interactions between molecules. Unlike chemical bonds, van der Waals interactions arise from quantum mechanical fluctuations of the electron density that leads to a weak but long-ranged attractive electrostatic force. Because van der Waals interactions are weak, a given molecule may crystallize in more than one structure. Different crystal structures that could lead to molecular crystals that possess markedly different physical and chemical properties can all be nearly the most favored structure. Accurate calculations are required to predict the structure that is the winner of this competition and to be able to design new molecular crystals. Through the portal of computer simulations, the PI will gain access to the vast configuration space of materials structure and composition. She will explore the uncharted territory of molecular crystals that have not been synthesized yet and predict their properties knowing only their elemental composition and the laws of quantum mechanics. In this way, promising candidate molecular crystals for specific applications may be identified and used to guide synthesis efforts.Genetic algorithms (GAs) are guided to the most promising configurations by computer simulation that implements the "survival of the fittest" principle of evolution. Combining structural "genes" of the fittest structures in the population lead to "offspring" that propagate desirable features, while random mutations are employed to maintain diversity. This approach is implemented in a GA software package, GAtor, for computers that can perform many operations at the same time. The PI will distribute the GAtor software package to the broader community.This award also supports educational activities. The goals of the educational plan are to: (i) impart discipline-specific knowledge and technical skills; (ii) develop the foundational skills of science and engineering, such as problem solving, critical thinking, and computational thinking; (iii) instill professional skills, such as literature research, scientific writing, and presentation skills; (iv) prepare students for a career; and (v) broaden the participation of women and underrepresented minorities. This will be achieved via research mentoring, teaching of graduate and undergraduate courses, and the "Women Leaders in Physics and Engineering" seminar series.TECHNICAL SUMMARYThe Division of Materials Research and the Division of Advanced Cyberinfrastructure contribute funds to this award. It supports computational research, algorithm development, and education on molecular crystals. The goal of the proposed research is computational structure prediction and design of molecular crystals with tailored properties from first principles. This will be achieved by developing a versatile genetic algorithm (GA) package, GAtor, capable of conducting both energy-based and property-based optimization with high accuracy and high efficiency. The research plan comprises two phases: (I) the Structure Prediction phase seeks to predict the most stable structure(s) of a molecular crystal, given a "stick diagram" of a single molecule- a grand challenge embodied by the Crystal Structure Prediction blind test; and (II) the Crystal Engineering from First Principles phase seeks to design molecular crystals with target properties for applications in organic electronics and photovoltaics by property-based GAs- an emerging paradigm in computational materials design. The PI will use density functional theory based simulations that include dispersion to accurately describe the potential energy landscape arising from van der Waals interactions. Many-body perturbation theory methods will be used to accurately describe excitonic properties. The educational component is aimed to: (i) impart discipline-specific knowledge and technical skills; (ii) develop the foundational skills of science and engineering, such as problem solving, critical thinking, and computational thinking; (iii) instill professional skills, such as literature research, scientific writing, and presentation skills; (iv) prepare students for a career; and (v) broaden the participation of women and underrepresented minorities. This will be achieved via research mentoring, teaching of graduate and undergraduate courses, and the "Women Leaders in Physics and Engineering" seminar series.