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以及量子化学计算来确定小型含硅团簇和纳米结构的结构和电子性质，特别是与天体物理相关的结构和电子性质。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大小的硅酸盐尘埃颗粒的化学演化尚不清楚。这些大小之间的中间物一定存在，但在观察中是难以捉摸的。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、光破碎模式和化学反应性来填补这一空白。这一结果不仅使这些粒子的天文探测成为可能，而且还为星周尘埃壳的理论模型提供了有价值的输入。当我们在此集中于硅氧化物、硅酸盐和相关分子的天体物理背景时，正在研究的物种在其他领域也很感兴趣，如半导体和材料科学以及纳米光子学。这些物质的光学性质在发展、改进和测试量子化学方法方面也引起了人们的普遍兴趣，这些方法能够可靠地预测所涉及的激发态，这在量子化学中仍然是一个具有挑战性的领域。

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.