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Removing the Barriers to the Calculation of Activation Energies, Activation Volumes, and Mechanistic Insight for Chemical Dynamics

消除化学动力学活化能、活化体积和机理洞察计算的障碍

基本信息

批准号：
1800559
负责人：
Ward Thompson
金额：
$ 45.67万
依托单位：
University of Kansas Center for Research Inc
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2022-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1800559&HistoricalAwards=false
关键词：
Removing Barriers Calculation Activation Energies

项目摘要

Ward Thompson of the University of Kansas is supported by an award from the Chemical Theory, Models, and Computational Methods program in the Division of Chemistry to develop methods for predicting the temperature dependence of dynamics in chemical systems. Changing such external properties is a key way to control chemistry in a laboratory or industrial setting. Thus, it is important to understand how these variables affect the timescales of the important motions involved in the chemistry. This knowledge also provides insight into the molecular-level motions that determine the timescale. The methods developed in this project, for example, allow the direct calculation of the temperature dependence of any timescale (such as the time for a chemical reaction to take place) from simulations at a single temperature. At the same time, they give information about the molecular interactions that influence the temperature dependence. Currently, no other method can provide such information. In addition to the behavior with temperature, the effect of other properties such as pressure or system composition may be calculated. While the approaches apply to any chemical system, the Thompson group is focusing on dynamics in liquids. The award also supports an outreach program for elementary school students to increase their interest in and motivation for science. It is designed to let the students see what scientists do and encourage them to view themselves as scientists through activities and interactions with graduate students and faculty. The methods developed fall into three categories: 1) Those enabling the calculation of activation energies for reactions and other dynamical processes from simulations at a single temperature. These approaches provide otherwise unattainable information: the contributions of different interactions to the activation energy. 2) Those evaluating changes in dynamical timescales with physical conditions other than temperature, such as pressure or chemical potential. This makes quantities like the activation volume available from simulations at a single pressure. 3) Approaches for calculating derivatives of rate constants and other dynamical timescales with respect to components of the underlying Hamiltonian, such as masses or potential parameters, to gain insight into mechanisms, force fields, and kinetic isotope effects.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.

堪萨斯大学的Ward Thompson获得了化学系化学理论、模型和计算方法项目的奖励，以开发预测化学系统中动力学温度依赖性的方法。改变这种外部性质是在实验室或工业环境中控制化学的关键方法。因此，重要的是要了解这些变量如何影响化学中涉及的重要运动的时间尺度。这些知识也提供了对决定时间尺度的分子水平运动的洞察。例如，该项目中开发的方法允许从单一温度下的模拟中直接计算任何时间尺度（例如化学反应发生的时间）的温度依赖性。同时他们给出了影响温度依赖性的分子相互作用的信息。目前，没有其他方法可以提供此类信息。除了随温度变化的特性外，还可以计算其他特性（如压力或系统组成）的影响。虽然这些方法适用于任何化学系统，但汤普森小组专注于液体动力学。该奖项还支持小学生的推广计划，以提高他们对科学的兴趣和动力。它的目的是让学生看到科学家做什么，并鼓励他们通过与研究生和教师的活动和互动，把自己看作是科学家。开发的方法分为三类：1）那些能够从单一温度下的模拟计算反应和其他动力学过程的活化能。这些方法提供了其他方法无法获得的信息：不同相互作用对活化能的贡献。2)那些评估在动力学时间尺度上与温度以外的物理条件（如压力或化学势）的变化。这使得在单一压力下的模拟中可以获得激活体积等量。 3)计算速率常数和其他动力学时标相对于基础哈密顿量分量（如质量或势参数）的导数的方法，以深入了解机制、力场和动力学同位素效应。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。