New Coupled-cluster Methods for Linear and Non-linear Valence and Core-level Spectroscopy in Gas and Condensed Phase

南加州大学的安娜·克里洛夫（Anna Krylov）获得了化学系化学理论、模型和计算方法项目的奖励，以开发新的理论方法、计算机算法和软件来描述分子和光在新体制下的相互作用（高能量、高强度等）。利用光来询问物质是光谱学的基础，它为揭示化学反应机制、材料和生物物体的结构和内在特性提供了最强大的工具。使用高能（x射线）和高强度辐射开辟了新的令人兴奋的机会，这激励了全球数十亿美元的先进光源设施的发展。这些设施中光束质量的最新进展极大地扩展了x射线的可能应用，引起了包括时间分辨和非线性制度在内的技术的扩散。这些新技术有望极大地扩展我们研究分子结构和动力学的能力，但只有当实验得到精确的理论工具来模拟这些现象时，它们的全部潜力才能实现。尽管付出了巨大的努力，但理论仍然落后于实验能力，这为数十亿先进光源设施的科学影响最大化创造了瓶颈。Krylov将通过开发新的电子结构方法来模拟气体和凝聚相中的线性和非线性核心能级光谱，从而弥补这一差距。研究计划包括培训和指导研究生和博士后在学术界和工业界的职业生涯，以及对研究基础设施的贡献。利用她之前的工作，Krylov将进一步扩展高可靠的耦合簇（CC）和运动方程CC （EOM-CC）方法，通过利用核心价分离（CVS）和阻尼响应理论（或复极化传播子，CPP）方法，到核心级电离和激发态领域。具体而言，她将进一步开发理论框架和有效的计算机代码，用于模拟E2PA（纠缠2PA）， PECD（光电子圆二色），MCD（磁性CD）和电子SFG（和频生成）光谱。她的目标是为UV-vis（价跃迁）和x射线（核心能级跃迁）领域建立一个统一的理论框架。继续与实验人员密切合作，指导和校准发展，并帮助设计新的实验和解释实验结果。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Anna Krylov of the University of Southern California is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry to develop new theoretical approaches, computer algorithms, and software to describe interaction of molecules and light in new regimes (high energy, high intensities, etc). Using light to interrogate matter is the basis of spectroscopy, which provides the most powerful set of tools for unraveling mechanisms of chemical reactions, structures and intrinsic properties of materials and biological objects. Using high-energy (X-rays) and high-intensity radiation opens new exciting opportunities, which motivate the worldwide development of multi-billion facilities for advanced light sources. Recent advances in beam quality in these facilities greatly expanded possible applications of X-rays, giving rise to a proliferation of techniques including those operating in time-resolved and non-linear regimes. These novel techniques promise to greatly expand our ability to interrogate molecular structure and dynamics, but their full potential can only be realized when experiment is augmented by accurate theoretical tools for modeling these phenomena. Despite significant efforts, the theory is still lagging behind the experimental capabilities, creating a bottleneck for maximizing the scientific impact of multi-billion advanced light source facilities. Krylov will bridge this gap by developing novel electronic structure methods for modeling linear and non-linear core-level spectroscopies in the gas and condensed phases. The research plans include training and mentoring of graduate students and postdocs for careers in academia and industry as well as contributions to the research infrastructure.Capitalizing on her previous work, Krylov will further extend highly reliable coupled-cluster (CC) and equation-of-motion CC (EOM-CC) methods to the domain of core-level ionized and excited states by exploiting core-valence separation (CVS) and damped response theory (or complex polarization propagator, CPP) approaches. Specifically, she will further develop theoretical framework and efficient computer codes for modeling E2PA (entangled 2PA), PECD (photoelectron circular dichroism), MCD (magnetic CD), and electronic SFG (sum-frequency generation) spectra. She aims to develop a uniform theoretical framework for both UV–vis (valence transitions) and X-ray (core-level transitions) domains. Continuing close collaborations with experimentalists guides and calibrate the developments, as well as helps to design new experiments and interpret the experimental results.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.