CAREER: Chemical Trends of Elements Under Pressure and their Effects to Forms and Properties of Materials

非技术总结这个职业奖项通过了解高压下元素的基本化学特征来支持设计新材料的研究和教育。所有物质都是由元素组成的，所有元素都根据它们在元素周期表中的位置而显示出特殊的化学性质。化学的一般规则是，元素的特征和行为是由原子最外层轨道的电子决定的。我们目前的化学知识和实践受到元素周期表中元素数量和这些元素可能存在的化学状态的限制。这个项目旨在揭示如何使用物理力来打破化学的上述界限。当这种情况发生时，现有元素可以极大地改变它们的化学特征和身份，表现得就像全新的元素一样。使用先进的计算技术，该项目将系统地探索可以通过利用改变元素化学性质的物理压力形成的新材料。结合一个新的受限空间中原子的量子力学模型，这个项目将理解压力将如何改变元素元素周期表。通过揭示元素在压力下的变化，这项工作可能会在很大程度上扩展材料的范围。它还可能产生关于如何利用新的化学来设计和获得具有不寻常性质的新材料以及了解地球内部和地外行星中元素的行为和分布的知识。原子和电子结构的计算机模拟将被纳入加州州立大学北岭分校本科生和研究生的早期课程。北岭分校是一所少数族裔服务机构，西语裔学生人数众多。它还将介绍给当地的社区大学和高中生，让他们对材料和化学有更深入的了解，并为他们未来的职业生涯提供新的技能和工具。技术总结这个职业奖项支持旨在推动材料设计和发现的计算和理论研究，方法是了解元素的基本化学性质(如反应性或氧化态)在压力下如何变化，以及如何利用这些知识制造具有不寻常和所需性能的材料。这一计划的灵感来自于最近的高压研究发现的一系列惊人现象，例如核心电子变得活跃并形成化学键，电子在间隙位置扮演阴离子的角色，以及惰性气体与离子化合物反应而不形成任何化学键。这些现象令人兴奋，因为它们不仅在最基本的水平上改变了化学，而且还可以极大地拓宽材料的形式和性质。深入和系统地了解元素在不同压力水平下的行为是必要的，但还不到位。这一新兴的极端条件下的材料领域很难用目前的高压实验直接研究，而且这些方法也很耗时和昂贵。快速、低成本的计算机模拟可以探索高压，有可能为实验提供指导。PI将使用基于量子力学的计算机模拟和自动晶体结构搜索方法来解决这些问题，方法是研究一系列包含聚焦元素的化合物的稳定性和成键特征。具体地说，PI将承担以下研究目标，探索：1)核心p和d核心电子的反应性及其与外部压力的关系，以及相应的成键特征和性质；2)二元三维金属化合物的逆化学现象；3)利用新型的加压化学设计和生产具有最高性能的新材料；4)通过一组小参数表示元素在不同压力水平下的化学行为的可能性，特别是元素周期表在高压下是否及如何变化。该项目通过一系列活动将研究和教育结合在一起，包括建立一个新的计算材料课程和实验室；培训学生并让他们参与尖端材料研究；以及组织午餐论坛和研讨会。此外，CSUN其他研究小组中选定的学生将被邀请作为客座研究员工作，并将计算方法整合到他们自己的研究主题中。该教育计划将有助于增加STEM地区代表性不足的学生的参与。它包括为来自代表性不足群体的学生提供探索材料科学研究、STEM教育以及相关教育和专业途径的多种机会的外联活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL SUMMARYThis CAREER award supports research and education in designing novel materials by understanding the basic chemical characteristics of elements under high pressure. All matter is composed of elements, and all elements show peculiar chemical properties depending on their positions in the periodic table. A general rule of chemistry is that the characteristics and behaviors of elements are determined by electrons of an atom's outermost orbital. Our current knowledge and practice of chemistry has been limited by the number of elements in the periodic table and the chemical states in which these elements could exist. This project aims to reveal how physical forces can be used to break the above boundary of chemistry. When this happens, the existing elements can drastically change their chemical characteristics and identities and behave like entirely new elements. Using advanced computational techniques, this project will systematically explore the new materials that can be formed by utilizing the physical pressures that alter the chemical properties of elements. Combining with a new quantum mechanics model of atoms in confined space, this project will apprehend how the pressure will transform the periodic table of elements. The work may largely extend the scope of materials by revealing the transformation of elements under pressure. It may also give rise to knowledge of how the new chemistry can be utilized in designing and obtaining new materials with unusual properties as well as in understanding the behavior and distribution of elements in the interior of Earth and extraterrestrial planets. The computer simulations of atomic and electronic structures will be incorporated into the early curriculum of undergraduate and graduate students in California State University Northridge, a minority serving institution with a large Hispanic enrollment. It will also be introduced to local community college and high school students, providing them with a deeper understanding of materials and chemistry and new skills and tools for their future careers. TECHNICAL SUMMARYThis CAREER award supports computational and theoretical research aimed to advance the design and discovery of materials by understanding how the basic chemical character of elements, such as reactivity or oxidation state, can change under pressure and how to utilize this knowledge to make materials with unusual and desired properties. This plan is inspired by a series of striking phenomena uncovered by recent high-pressure research, such as core electrons that become reactive and form chemical bonds, electrons that play the role of anions at the interstitial sites, and noble gases that react with ionic compounds without forming any chemical bond. These phenomena are exciting because they not only alter the chemistry at the very fundamental level, but also can greatly broaden the form and the properties of materials. An in-depth and systematized understanding of how elements behave under different levels of pressure is essential but not yet in place. This emerging area of materials under extreme conditions is difficult to directly study using current high-pressure experiments, and these methods are also time consuming and costly. Rapid and low-cost computer simulation can explore high pressure and have potential to provide guidance to experiment. The PI will employ computer simulations based on quantum mechanics and automatic crystal structure search methods to address these issues by studying the stability and bonding features of a series of compounds containing focused elements. Specifically, the PI will undertake the following research objectives, exploring: 1) the reactivity of inner core p and d core electrons and its relation to external pressures, and the corresponding bonding feature and the properties; 2) a reverse chemistry phenomena of binary 3d metal compounds; 3) the use of the novel chemistry under pressure in designing and producing new materials with superlative properties; 4) the possibility of representing the chemical behavior of elements under different levels of pressure by a small set of parameters, especially whether and how the periodic table changes under high pressure. The project integrates research and education through a set of activities including establishing a new computational materials course and lab; training and involving students in cutting edge materials research; and organizing lunch forums and seminars. Furthermore, selected students in other CSUN research groups will be invited to work as guest researchers and integrate computational methods into their own research topics. The educational plan will help increase the involvement of students who are underrepresented in STEM areas. It includes outreach activities to provide students from underrepresented groups with multiple opportunities to explore materials science research, STEM education, and associated educational and professional pathways.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.