CAREER: Developing Quantum Nanogeochemistry for Molecular Studies and Inclusive Education

美国国家科学基金会化学部的环境化学科学项目支持爱荷华大学的Sara E. Mason教授的研究，她将指导一个项目，其最终目标是发展量子纳米地球化学作为一个平台，(1)提供对环境纳米粒子（ENP）结构-反应性的基本理解，(2)合并不同的ENP反应性理论，以及，(3)招收社区学院（CC）学生，为他们提供大学水平的培训机会。研究策略是对两类ENPs进行基于密度泛函数理论（DFT）的模拟：模拟为巨型铝阳离子（gap）的水性氢氧化铝和模拟为周期板模型（psm）的矿物质-水界面。确定适合每种模型类别的反应性问题，并设计系统模拟实验，使用比较来分离控制反应性的因素。这些项目旨在将gap和psm的原子模拟结果发展为ENP反应性的新概念模型，这一目标将支持或消除现有的理论。为此，将利用模型之间的区别，例如，gap是跟踪轨道相互作用反应性的理想模型，因为它们是真正的纳米粒子，并且预计较少的电子态参与界面键合。而且，这些氢氧化铝没有d电子，所以它们的电子结构不像结构相似的氢氧化铁那么复杂。同时，PSM的几何形状是探索吸附诱导的长范围键弛豫和相对能量学如何在键价（BV）框架中被捕获的理想选择。一些提议的模拟将涉及首次计算，例如后来描述的DFT + COSMO（类传导筛选模型）+ (delta)H2O（部分显式水化）方法，用于模拟含水Al30 (GAP)，并推导表面特异性Hubbard U修正，以准确模拟由强相关矿物氧化物组成的psm。这项拟议的工作将使人们能够更好地预测水污染物的封存，最终可能导致新的水修复策略。每个研究项目都将支持研究生和本科生的培训，重点将放在“活到老学到老”（NTLL）项目及其使命上，即让社区大学生参与教育和研究活动，为培养他们成为下一代科学家提供机会。努力将研究成果组织到DFT数据库中，并将在相关的数据管理计划中报告，确保从原子模拟中获得的基本信息将传播到研究界，无论是否未能率先提出概念模型。统一的研究和教育计划适合首席研究员的优势、背景和承诺，以发展量子纳米地球化学作为环境化学科学的一个重要领域。

The Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation supports the research of Professor Sara E. Mason at the University of Iowa who will direct a project whose ultimate goal is to develop quantum nanogeochemistry as a platform, (1) to provide fundamental understanding of environmental nanoparticle (ENP) structure-reactivity, (2) to merge distinct theories of ENP reactivity, and, (3) to recruit community college (CC) students for training opportunities at the university level. The research strategy is to carry out Density Functional Theory (DFT)-based simulations on two classes of ENPs: Aqueous aluminum hydroxides modeled as Giant Aluminum Polycations (GAPs) and mineral-water interfaces modeled as Periodic Slab Models (PSMs). Reactivity questions that are suited to each model category are identified, and systematic simulation experiments are designed using comparisons to isolate what controls reactivity. The projects are designed to develop atomistic simulations results of both GAPs and PSMs into new conceptual models for ENP reactivity, a goal that will support or dispel existing theories. For this purpose, the distinctions between the models will be exploited, for example, GAPs are ideal models for tracking reactivity with orbital interactions because they are truly nanoparticulate, and fewer electronic states are expected to participate in interfacial bonding. Also, these aluminum hydroxides do not have d electrons, so they have a less complicated electronic structure than similarly structured iron hydroxides. Meanwhile, the PSM geometry is ideal for probing how adsorption-induced long range bond relaxation and relative energetics can be captured in a Bond Valence (BV) framework. Several of the proposed simulations will involve first time calculations, such as the later described DFT + COSMO (conduction-like screening model)+ (delta)H2O (partial explicit hydration) method for simulating the aqueous Al30 (GAP) and deriving surface-specific Hubbard U corrections to accurately model PSMs comprised of strongly correlated mineral oxides. The proposed work will enable improved predictions about the sequestration of aqueous contaminants that could ultimately lead to new water remediation strategies. Each research project will support the training of graduate and undergraduate students, and a major emphasis will be placed on the "Never Too Late to Learn" (NTLL) program and its mission to engage community college students in education and research activities that will extend opportunities to train them as the next generation scientists. Efforts to organize research outcomes into DFT databases that will be reported in the associated Data Management Plan, ensure that the fundamental information obtained from the atomistic simulations will be disseminated to the research community, regardless of any failure to pioneer the proposed conceptual models. The unified research and education plans are suited to principal investigator's strengths, background, and commitment to develop quantum nanogeochemistry as a vital field in environmental chemical science.