EUV Photoexcitation and Emission of N2 at Low Temperatures

这个项目将提供必要的光激发和发射数据，通过研究氮分子的里德堡和价态与大气中氮、中性原子(NI)和电离(NII)氮排放之间的强烈相互作用，了解分子氮(N2)在行星大气中的重要分子物理和作用。当实验在光学薄的条件下进行时，高分辨率荧光激发光谱的测量将确定绝对预解离产额。这项研究的第二部分将测量特定的绝对分枝率。第三个重要的活动将测量NI和NII发射的绝对荧光产生截面，通过N_2的光解离激发和解离光离激发。最后一项任务是与氮的同位素类似的工作，对当前项目的范围来说可能过于雄心勃勃，但将有助于理解在行星大气中观察到的氮同位素异常。这项工作将使用现有的实验设备，为观察荧光光谱和确定绝对荧光产生截面提供快速、高效和经济高效的手段。这些实验程序是由PI的团队开发的，将在适合外部巨行星和卫星大气的温度范围内进行。这些数据是对土星、土卫六、Triton和冥王星的氮气辉光模型进行准确定量分析和评估所必需的。这些结果将为原子和分子理论家、大气模型师和光学天文学家提供帮助。其中一些光谱特征作为全球遥感的替代方案或作为现有波段的补充测量具有相当大的意义。这项研究将继续为博士后助理、研究生和本科生在培训和研究经验方面做出成功的努力。该奖项由2009年美国复苏和再投资法案(公法111-5)资助。

AST-0906158WuThis project will provide the necessary photo-excitation and emission data required to understand the important molecular physics and role in planetary atmospheres of molecular nitrogen (N2) by investigating the strong interactions among the Rydberg and valence states of N2 and the atmospheric N2, neutral atomic (NI) and ionized (NII) nitrogen emissions. Measurement of high-resolution fluorescence excitation spectra will determine the absolute predissociation yields when the experiments are conducted under optically thin conditions. The second part of this study will measure specific absolute branching ratios. The third significant activity will measure absolute fluorescence production cross-sections for the NI and NII emissions through photodissociative excitation and dissociative photoionization excitation of N2. The last task, similar work with isotopes of nitrogen, may be too ambitious for the scope of the current project, but would help to understand the nitrogen isotope anomaly observed in planetary atmospheres.The work will use an existing experimental apparatus that provides a rapid, efficient, and cost-effective means for observing fluorescence spectra and determining the absolute fluorescence production cross-sections. The experimental procedures have been developed by the PI's group, and will be conducted over a temperature range appropriate to the atmospheres of outer giant planets and satellites. These data are required for accurate quantitative analysis and evaluation of the nitrogen airglow models of Saturn, Titan, Triton, and Pluto.The results will benefit atomic and molecular theorists, atmospheric modelers, and optical astronomers. Several of the spectral features are of considerable interest as remote global sensing alternatives or as complementary measurements to existing bands. The study will continue successful efforts in training and research experiences for postdoctoral associates, graduate and undergraduate students.This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).