State-Resolved Vibrational Spectra of Fluxional Protonated Water Clusters via Tensor Network States

在化学系化学理论、模型和计算方法（CTMC）项目的支持下，加州大学默塞德分校的Henrik R. Larsson正在开发新的理论方法，用于解开质子化水团簇中的量子效应。这些团簇是理解水的基本特性的关键，比如它的酸度，这取决于许多复杂的量子相互作用。Henrik R. Larsson和他的研究小组将开发一种方法，旨在有效和准确地模拟质子化水团簇，其复杂性相对于以前的工作增加了近一个数量级。在这项研究中开发的方法有望普遍适用于广泛领域的量子系统，包括能源科学、天文学和光化学。Larsson博士计划在量子动力学网络内共同组织一个跨学科研讨会，讨论开发模拟量子系统的新方法，将不同领域的科学界聚集在一起。Larsson博士计划通过在暑期学校授课来吸引分子量子动力学这一激动人心的领域的早期职业科学家。首席研究员还旨在通过ACS项目种子，让经济状况不佳的高中生和第一代本科生参与与该项目直接相关的研究活动。加州大学默塞德分校的Henrik R. Larsson和他的研究小组将开发全维振动量子动力学模拟方法。他们将开发基于张量网络状态的方法，利用密度矩阵重整化群（DMRG）和多层多构型时变Hartree （ML-MCTDH）方法的力量。他们将应用这些新方法来了解有限温度、同位素取代和微溶剂化对质子化水团簇的质子转移运动和红外光谱的影响。他们将优化和分析导致难以理解的实验光谱的高激发波函数。将通过显式波函数比较和降维模拟来分析集群之间的差异和相似性。在这个程序中开发的方法预计将广泛适用于振动流态的研究之外，例如，将可能对模拟非绝热动力学和计算激发态有用。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。

With support from the Chemical Theory, Models and Computational Methods (CTMC) program in the Division of Chemistry (CHE), Henrik R. Larsson of the University of California, Merced is developing new theoretical methods that will be applied to unravel quantum effects in protonated water clusters. These clusters are key to understanding the fundamental properties of water, such as its acidity, which depend on many complex quantum interactions. Henrik R. Larsson and his research group will be developing methods that are designed to enable an efficient and accurate simulation of protonated water clusters with nearly an order of magnitude increase in complexity relative to previous work. The methods developed in this research are expected to be generally applicable to a broad class of quantum systems in a wide range of fields including energy sciences, and astro- and photochemistry. Dr. Larsson plans to co-organize an interdisciplinary workshop within the Quantum Dynamics Network about developing new methods for simulating quantum systems to bring scientific communities from different fields together. Plans are in place for Dr. Larsson to engage early career scientists in the exciting field of molecular quantum dynamics by lecturing at a summer school. The principal investigator also aims to involve economically disadvantaged high school students, through ACS Project Seed, and first generation undergraduate students in research activities that are directly linked to this project.Dr. Henrik R. Larsson and his research group at the University of California, Merced will develop methods for full-dimensional vibrational quantum dynamics simulations. The methods they will develop are based on tensor network states, leveraging the power of the density matrix renormalization group (DMRG) and of the multilayer multi-configurational time-dependent Hartree (ML-MCTDH) method. They will apply these new methods to understanding the effects of finite temperature, isotope substitution and microsolvation on the proton transfer motion and the infrared spectrum of protonated water clusters. They will optimize and analyze highly excited wavefunctions that lead to poorly understood experimental spectra. Differences and similarities between the clusters will be analyzed by means of explicit wavefunction comparisons and by reduced-dimensional simulations. The methods developed in this program are expected to be broadly applicable beyond the study of vibrational fluxional states and, for example, will likely be useful for simulating nonadiabatic dynamics and for computing excited electronic states.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.