Optical spectra of silicon-bearing clusters and nanostructures of astrophysical interest

我们建议通过振动和光学激光光谱和量子化学计算来确定小的含硅团簇和纳米结构的结构和电子性质，特别是那些与天体物理相关的性质。在星际介质中，从小的硅氧化物、硅酸盐和相关分子到大的微米尺寸的硅酸盐尘埃颗粒的化学演化知之甚少。这些大小机制之间的中间体必须存在，但难以观测。这些物种的实验室光谱在文献中几乎是不可用的。该项目的目的是通过确定这些物种的光学和光化学性质、稳定性、光致碎裂模式和化学反应性来填补这一空白。这些结果不仅可以使这些粒子的天文探测，但也提供了有价值的输入拱星尘埃壳的理论模型。虽然我们在这里集中在硅氧化物，硅酸盐和相关分子的天体物理背景下，正在调查的物种也在其他领域，如半导体和材料科学和纳米光子学的兴趣。这些物质的光学性质也是开发，改进和测试量子化学方法的普遍兴趣，这些方法能够可靠地预测所涉及的激发态，这仍然是量子化学中具有挑战性的领域。

We propose to determine the structural and electronic properties of small silicon-bearing clusters and nanostructures, especially those of astrophysical relevance, by means of vibrational and optical laser spectroscopy and quantum chemical calculations. The chemical evolution from small silicon oxides, silicates, and related molecules to large micrometer-sized silicate dust particles in the interstellar medium is poorly understood. Intermediates between these size regimes must exist but are elusive to observations. Laboratory optical spectra of these species are virtually unavailable in the literature. The purpose of this project is to fill this gap by determining the optical and photochemical properties, stabilities, photofragmentation patterns, and chemical reactivity of these species. The results may not only enable the astronomical detection of those particles but also provide valuable input to theoretical models of circumstellar dust shells. While we concentrate herein on the astrophysical context of silicon oxides, silicates, and related molecules, the species under investigation are also of interest in other fields, such as semiconductor and materials sciences and nanophotonics. The optical properties of these species are also of general interest with respect to developing, improving, and testing quantum chemical approaches that enable the reliable prediction of the involved excited states, which has remained a challenging field in quantum chemistry.