Proposed Laboratory Simulation Studies of EUV-VUV Photolysis of Cosmic Icy Systems

AST 0604455Wu有了这个奖项，Wu博士和他的同事们将进行天体物理冰类似物的光解研究。他们将在相同的实验条件下，在同一个冰真空室中同时研究给定冰系统中的光子诱导化学反应和光子溅射。他们将确定在冰系统中形成的分子类型以及从冰面上脱落的分子类型，量化它们的产量，了解它们的生产机制，并确定它们在天文环境中的重要性。近年来，在天文环境和行星系统中化学过程的实验室模拟方面取得了很大进展。本文的主要工作包括对冰粒和冰的光子辐照和带电粒子碰撞的研究。这些研究对于理解星际介质的演化和太阳系原始物质的化学组成是至关重要的。实验室模拟现在已经成为破译这些复杂现象的主要工具，这些现象可能在天体物理学和天体生物学中具有许多其他重要意义。吴博士将继续他的实验室研究工作，通过测量现场傅里叶变换红外（FTIR）观测天文冰类似物的光解样品。此外，他们还将利用四极质谱仪（QMS）对光子溅射进行同步测量。 除了原位研究外，还将采用色谱技术分析光解残留物。拟议工作所需的许多精密设备和先进的实验技术已由这些研究人员在以前资助的项目中开发，并可用于本拟议项目。台湾同步辐射研究中心的可调谐强同步辐射光源将提供所需的光子。 选择照射冰样品的光子波长将主要对应于突出的太阳氦、氦离子和氢谱线。要研究的冰系统将包括含有H2O、CO、CO2、N2、NH3、CH4、CH3OH、SO2和其他相关物质的宇宙冰类似物。所获得的结果对我们理解巨行星、彗星、星际介质、分子云和原恒星区域的富水冰卫星中的化学和质量演化和合成特别相关。本项目将培养一名研究生，特别是涉及与同步辐射设施的合作。 吴博士过去曾与国立中央大学和台湾国家同步辐射研究中心的科学家合作，并将继续与该项目合作。研究成果将用于研究生和本科生的高级课程教学，并将在科学会议上发表。更好地了解冰的光化学和热物理学也可以帮助我们考虑适当的预防措施，以防臭氧空洞扩大，使更多的紫外线辐射穿透地球对流层。

AST 0604455WuWith this award, Dr. Wu and colleagues will carry out a photolysis study of astrophysical ice analogs. They will simultaneously investigate photon-induced chemical reactions and photon sputtering in a given ice system under the same experimental conditions in the same ultrahigh vacuum chamber. They will identify the type of molecules that form in the ice systems and that come off the ice surfaces, quantify their production yields, understand their production mechanisms, and ascertain their significance in astronomical environments. Recently, much progress has been made in the area of laboratory simulations of chemicalprocesses present in astronomical environments and in planetary systems. The body of this workincludes the study of photon irradiation and charged particle impact of ice grains and ices. Suchstudies are fundamental to the understanding of the evolution of the interstellar medium, and thechemical composition of primitive material in our solar system. Laboratory simulation has nowbecome a major tool in deciphering these complex phenomena which could have many otherimportant implications in astrophysics and astrobiology. Dr. Wu will continue his laboratory research efforts through measurements of in-situ Fourier Transform Infrared (FTIR) observations of the photolyzed samples of astronomic ice analogs. In addition, they will carry out simultaneous measurements of photon sputtering by utilizing a Quadrupole Mass Spectrometer (QMS). Chromatography techniques will be employed to analyze the photolyzed residues in addition to the in-situ studies. Much of the sophisticated equipment and advanced experimental techniques required for the proposed work have been developed by these researchers in previously funded projects and are available to this proposed project. A tunable intense synchrotron radiation light source available at the Synchrotron Radiation Research Center, Taiwan, will provide the required photons. The photon wavelengths selected to irradiate the icy samples will mainly correspond to the prominent solar helium, helium ion, and hydrogen lines. The ice systems to be investigated will include cosmic ice analogs containing H2O, CO, CO2, N2, NH3, CH4, CH3OH, SO2, and other relevant species. The results to be obtained are particularly relevant to our understanding of chemical and mass evolutions and synthesis in water-rich icy satellites of the giant planets, comets, the interstellar medium, molecular clouds, and protostellar regions.This project will train a graduate student, especially involving working with a synchrotronradiation facility. Dr. Wu has collaborated with scientists in the National Central University and the National Synchrotron Radiation Research Center in Taiwan in the past and will continue the collaborative efforts with this project. The research results will be used in teaching advanced courses for graduate and undergraduate students, and will be presented at scientific conferences. A better understanding of the photochemistry and photophysics of ices could also help us consider appropriate preventive measures in the event of the expanding ozone-hole that allows more ultraviolet radiation to penetrate to Earths troposphere.***