First-Principles Simulation of Electronic Excitation Dynamics in Water and DNA under Proton Irradiation

质子辐照下水和 DNA 中电子激发动力学的第一性原理模拟

• 批准号: 1565714
• 负责人: Yosuke Kanai
• 金额: $ 37.27万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2020-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1565714&HistoricalAwards=false
• 关键词: First; Principles; Simulation; Electronic; Excitation

Yosuke Kanai of the University of North Carolina at Chapel Hill is supported by an award from the Chemical Theory, Models and Computational Methods program for computational work related to proton beam cancer therapy. Proton beam cancer therapies work by targeting cancer cells with high-energy protons. These protons damage the cancer cells by breaking the double strands of their DNA. In recent years, other particles, such as alpha-particles and carbon-ions, have been considered as alternatives to protons for cancer therapies. The energetic protons or other particles transfer their energy to the water and DNA by exciting their electrons. There is a strong need for a better understanding of the energy transfer process and electronic excitation process. Using massively parallel computers, Kanai and his research group develop and apply computational methods for simulating the energy transfer and electronic excitation process. Both graduate students and undergraduate students participate in this research.A new large-scale, real-time, time-dependent density functional theory (TDDFT) method is employed to study electronic excitation dynamics in liquid water and solvated DNA under proton, alpha-particle and carbon-ion irradiation. The energy transfer from the high-energy ions depends significantly on the particle velocity. The perturbing electric field from the energetic ion is highly heterogeneous at the molecular scale. Using the real-time TDDFT method, the excitation process is investigated in detail as a function of the ion velocity and type (protons, alpha-particles, and carbon-ions). The energy transfer rate from the ions to electronic excitations in liquid water is determined from non-equilibrium simulations, and a microscopic understanding of the excitation dynamics in liquid water and solvated DNA is developed. Improving scalability of real-time TDDFT code on massively parallel computers and the exchange-correlation approximation for describing the dynamical energy transfer process are two important aspects of this investigation. Dr. Kanai also develops novel teaching computational tools for teaching time-dependent quantum mechanics in advanced chemistry courses.

北卡罗来纳大学教堂山分校的 Yosuke Kanai 因与质子束癌症治疗相关的计算工作而获得化学理论、模型和计算方法项目的奖项支持。质子束癌症疗法通过用高能质子靶向癌细胞来发挥作用。 这些质子通过破坏癌细胞的 DNA 双链来损伤癌细胞。 近年来，其他粒子，例如α粒子和碳离子，已被认为是癌症治疗中质子的替代品。 高能质子或其他粒子通过激发电子将能量转移到水和 DNA 中。 迫切需要更好地了解能量转移过程和电子激发过程。 卡奈和他的研究小组使用大规模并行计算机开发并应用计算方法来模拟能量转移和电子激发过程。 研究生和本科生都参与了这项研究。采用一种新的大规模、实时、时间相关的密度泛函理论（TDDFT）方法来研究质子、α粒子下液态水和溶剂化DNA中的电子激发动力学和碳离子辐照。高能离子的能量转移很大程度上取决于粒子速度。 高能离子产生的扰动电场在分子尺度上是高度异质的。使用实时 TDDFT 方法，详细研究了激发过程作为离子速度和类型（质子、α 粒子和碳离子）的函数。液态水中从离子到电子激发的能量转移速率是通过非平衡模拟确定的，并且发展了对液态水和溶剂化 DNA 中激发动力学的微观理解。提高大规模并行计算机上实时 TDDFT 代码的可扩展性和用于描述动态能量传输过程的交换相关近似是本研究的两个重要方面。金井博士还开发了新颖的教学计算工具，用于在高级化学课程中教授时间依赖性量子力学。