Electronic spectroscopy of astrophysically important silicon-bearing molecules

含有硅的分子是关键的反应中间体，被认为是进化恒星中尘埃的祖先。这个研究项目将产生关于小碳化硅（含有硅和碳的分子）的新的光谱数据，这些碳化硅存在于尘埃形成区域和进化的碳星的星周包层中。这项研究的结果将有助于确定这些分子的结构和性质，并加快无线电和红外波长的实验室搜索。这将使它们在太空中得到明确的识别，使天文学家能够更好地了解星周环境的条件，并揭示一些对星际尘埃知之甚少的性质。该项目将有助于博士后学者的专业发展，培养实验室天体物理学先进方法的研究生，为本科生提供研究机会，并使来自非传统背景的当地公立高中学生接触到光谱学的前沿研究。利用先进的激光光谱技术，包括二维激光诱导荧光（2DF）和受激发射泵浦（SEP），研究人员将研究SiC2、Si2C和其他含硅瞬态分子的电子光谱。利用这些分子的强光学跃迁，SEP将提供高激发振动水平下的旋转振动跃迁的广泛概述，产生足够精确的光谱常数，以显着降低实验室微波搜索所需的频率范围。同样，2DF将用于解开Si2C的复杂光谱，并加快寻找非极性或弱极性含硅分子或含有其他丰富的星周元素的分子。互补的质量分辨共振电离实验将用于确保分子鉴定。所研究的一些分子在薄膜制造中也很重要，因此了解它们的光谱可以帮助阐明和改进先进光学和电子设备的制造工艺。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Molecules containing silicon are key reactive intermediates and are thought to be the progenitors of dust in evolved stars. This research project will generate new spectroscopic data on small silicon carbides – molecules containing silicon and carbon – that reside in the dust-forming regions and circumstellar envelopes of evolved carbon stars. Results from the study will allow determination of the structures and properties of these molecules and expedite laboratory searches at radio and infrared wavelengths. This will permit their unambiguous identification in space, allowing astronomers to better understand the conditions within circumstellar environments and shed some light on the poorly understood nature of interstellar dust. This project will contribute to the professional development of a postdoctoral scholar, train graduate students in advanced methods of laboratory astrophysics, provide research opportunities to undergraduate students, and expose local public high school students from non-traditional backgrounds to cutting edge research in spectroscopy.Using advanced laser spectroscopy techniques, including two-dimensional laser induced fluorescence (2DF) and stimulated emission pumping (SEP), the investigators will study the electronic spectra of SiC2, Si2C, and other silicon-bearing transient molecules. Exploiting the strong optical transitions of these molecules, SEP will provide a broad overview of rovibrational transitions within highly excited vibrational levels, yielding spectroscopic constants of sufficient accuracy to significantly reduce the frequency range required for laboratory microwave searches. Similarly, 2DF will be used to unravel the complex optical spectrum of Si2C and expedite searches for non-polar or weakly polar silicon-bearing molecules or ones containing other abundant circumstellar elements. Complementary mass-resolved resonant ionization experiments will be used to secure the molecular identifications. Some of the molecules investigated are also important in thin film fabrication, so a knowledge of their optical spectra could help elucidate and improve the manufacturing processes of advanced optical and electronic devices.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.