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RUI: Photoionization, Time Delay, Positronium Formation, and Ion Impact Studies of Fullerenes, Endofullerenes, and Atoms

RUI：富勒烯、内富勒烯和原子的光电离、时间延迟、正电子形成和离子撞击研究

基本信息

批准号：
1806206
负责人：
HIMADRI CHAKRABORTY
金额：
$ 30万
依托单位：
Northwest Missouri State University
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：
2018-08-15 至 2022-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1806206&HistoricalAwards=false
关键词：
RUI Photoionization Time Delay Positronium

项目摘要

By shining the laser light on an atom or by colliding the atom with charged particles one can probe the atom's response to such external stimuli. These are powerful scientific methods to learn fundamental properties of materials. Using these techniques to systems more complex than atoms and of direct applied interest is therefore beneficial for the advancement of basic science and technology. The systems to be studied in the current research are Buckminster fullerenes and other larger fullerenes, including atoms/clusters caged inside these molecules, called endofullerenes. These materials hold the promise of exciting applications in areas including quantum computations, superconductivity, biomedical fields, drug delivery research, magnetic resonance imaging, and organic photovoltaics. Hence, understanding the physical and chemical structure and response properties of these systems, including the influence of the fullerene cage on the behavior of the confined species, are matters of great scientific interest. Using large scale computer simulations the program aims to investigate how electrons inside the systems collectively interacts with each other to move internally or to exit the system and how much time they spend to reach the detector. How do the structure and geometry of the system play roles in the mechanism? This will be investigated both for light and fast-ion impact. By choosing exotic antiparticles like positrons to impact on fullerenes the study of the formation of electron-positron pairs, the positronium, is a novel direction of the program.Numerical methods to be employed to model the systems and their response are based on Density Functional Theory. These methods will also be used to calculate the intensity of the emerging electron flux from the system along a specific direction and/or in all directions. From the complex variation of the detected electron flux as a function of the laser energy or the ion-impact energy researchers will extract valuable information about the system. Furthermore, the time of flight of the electrons from the irradiated target to the detector will be computed and the variation in this flight-time as a function of laser frequency will enable further insights into the scientific processes. Following the impact of positrons, the formation of the positronium (Ps) is a vital process in nature, although no attempt of Ps formation using gas-phase fullerene systems has been made until recent research that came from this program. The science to be learned from the study of Ps formation should be universal for Ps formation from nanosystems ushering new directions of Ps spectroscopy. In general, results are expected to motivate experiments and induce collaborations with experimental groups. Students and postdoctoral researchers will be involved for excellent experience in education and opportunities to become expert researchers.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.

通过将激光照射在原子上或将原子与带电粒子碰撞，人们可以探测原子对此类外部刺激的反应。这些是了解材料基本特性的强大科学方法。因此，将这些技术用于比原子更复杂且具有直接应用价值的系统有利于基础科学和技术的进步。当前研究中要研究的系统是巴克明斯特富勒烯和其他较大的富勒烯，包括笼在这些分子内部的原子/簇，称为内富勒烯。这些材料有望在量子计算、超导、生物医学领域、药物输送研究、磁共振成像和有机光伏等领域产生令人兴奋的应用。因此，了解这些系统的物理和化学结构以及响应特性，包括富勒烯笼对受限物种行为的影响，具有重大的科学意义。该项目旨在使用大规模计算机模拟来研究系统内部的电子如何集体相互作用以在内部移动或退出系统，以及它们到达探测器所需的时间。系统的结构和几何形状如何在机制中发挥作用？这将针对光和快离子撞击进行研究。通过选择正电子等奇异反粒子来影响富勒烯，研究电子-正电子对（正电子素）的形成是该项目的一个新方向。用于模拟系统及其响应的数值方法基于密度泛函理论。这些方法还将用于计算系统沿特定方向和/或所有方向出现的电子通量的强度。从检测到的电子通量随激光能量或离子撞击能量变化的复杂变化中，研究人员将提取有关系统的有价值的信息。此外，还将计算电子从被照射目标到探测器的飞行时间，并且该飞行时间作为激光频率函数的变化将使人们能够进一步了解科学过程。正电子撞击后，正电子素 (Ps) 的形成是自然界中一个重要的过程，尽管直到最近该项目的研究才尝试使用气相富勒烯系统形成 Ps。从 Ps 形成研究中学到的科学应该对于纳米系统 Ps 形成具有普遍性，从而开创 Ps 光谱学的新方向。一般来说，结果有望激发实验并诱导与实验组的合作。学生和博士后研究人员将参与其中，获得卓越的教育经验和成为专家研究人员的机会。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。

项目成果

期刊论文数量（18）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

A dynamical (e,2e) investigation into the ionization of pyrazine

DOI：
10.1016/j.cplett.2021.139000
发表时间：
2021-10
期刊：
Chemical Physics Letters
影响因子：
2.8
作者：
Darryl B Jones;E. Ali;H. Chakraborty;C. Ning;G. García;D. Madison;M. Brunger
通讯作者：
Darryl B Jones;E. Ali;H. Chakraborty;C. Ning;G. García;D. Madison;M. Brunger

A density functional theory based comparative study of hybrid photoemissions from Cl@C60, Br@C60 and I@C60

DOI：
10.1140/epjd/e2020-10140-6
发表时间：
2020-03
期刊：
The European Physical Journal D
影响因子：
0
作者：
D. Shields;R. De;E. Ali;M. Madjet;S. Manson;H. Chakraborty
通讯作者：
D. Shields;R. De;E. Ali;M. Madjet;S. Manson;H. Chakraborty

Resonant Charge-Transfer in Grazing Collisions of H− with Vicinal Nanosurfaces on Cu(111), Au(100) and Pd(111) Substrates: A Comparative Study

H 与 Cu(111)、Au(100) 和 Pd(111) 基底上邻位纳米表面掠碰撞中的共振电荷转移：比较研究

DOI：
10.3390/atoms7030089
发表时间：
2019
期刊：
Atoms
影响因子：
1.8
作者：
Shaw, John;Monismith, David;Zhang, Yixiao;Doerr, Danielle;Chakraborty, Himadri S.
通讯作者：
Chakraborty, Himadri S.

Shrinking diffraction “fringes” in positronium formation from C 60 to C 240

正电子素形成过程中从 C 60 到 C 240 的衍射收缩“条纹”