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Kanai的Yosuke kanai得到了与质子束癌治疗相关的计算工作的化学理论，模型和计算方法计划的奖项。质子束癌疗法通过用高能质子靶向癌细胞来起作用。 这些质子通过打破其DNA的双链破坏了癌细胞。 近年来，其他颗粒（例如α粒子和碳离子）被认为是癌疗法质子的替代品。 能量质子或其他颗粒通过刺激电子将能量传递到水和DNA。 非常需要更好地了解能量传输过程和电子激发过程。 Kanai及其研究组使用大量平行的计算机开发并应用计算方法来模拟能量传输和电子激发过程。 研究生和本科生都参加了这项研究。采用了一种新的大型，实时，时间依赖性的密度功能理论（TDDFT）方法，用于研究液态水中的电子激发动力学，在质子，α-汤匙和碳-ion辐射下进行溶剂化DNA。来自高能离子的能量转移显着取决于粒子速度。 在分子尺度上，来自能量离子的扰动电场是高度异质的。使用实时TDDFT方法，对激发过程进行了详细研究，这是离子速度和类型（质子，α粒子和碳离子）的函数。通过非平衡模拟确定了从离子到电子激发的能量转移速率，并对液态水和溶剂化DNA的激发动力学有微观理解。在大规模平行的计算机上提高实时TDDFT代码的可扩展性以及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。 Kanai博士还开发了新型的教学计算工具，用于在高级化学课程中教学时间依赖时间量子力学。