High-resolution molecular spectroscopy using laser and synchrotron radiation

分子发射或吸收的不同波长的光-分子光谱-编码了关于被观察物种的内部结构和固有物理的丰富信息。每个分子的光谱都是独一无二的，可以像指纹一样用来识别它。这种特性非常强大，尤其是在天体物理学中，因为我们从遥远的恒星、星系和星际介质接收到的唯一信息来自它们产生或吸收的光。这项提议描述了一个研究计划，记录已知或潜在与天体物理学相关的物种的分子光谱。我们研究的许多分子非常不稳定，因为它们与大气气体反应并迅速被破坏-但在物质密度低的太空中，它们会持续很长时间。我们通过用激光脉冲从真空室中的棒上剥离材料来制造这些不稳定的分子。然后，热的物质羽流与快速移动的氦气射流反应，氦气射流中夹带着稳定的反应物分子，如甲烷或甲醇，产生太空中发现的不稳定物质。喷流与波长可以连续变化的激光束交叉，当波长与吸收波长相匹配时，分子发出荧光，产生我们可以检测到的信号以绘制光谱。我们专门研究含有金属原子的分子，金属原子来自于棒，并且与来自于反应气体的配体结合。含金属的分子，如FeH和CrH; FeO，VO和TiO;以及MgNC和MgCN已经在恒星（包括我们的太阳）的大气中观察到。我们将寻找像FeP，VP和TiP这样的物种，它们有一天可能会在太空中被观察到。位于SK萨斯卡通的加拿大光源同步加速器的建设为分子光谱实验增加了一个令人兴奋的新可能性-获得非常长波长的强烈和良好准直的光。同步加速器光使我们能够在电磁波谱的困难的2-30太赫兹区域快速获得极高质量的光谱，其中许多天体物理学感兴趣的大分子的基本振动所在。许多目前活跃的卫星仪器对这个区域很敏感，我和我的学生收集的数据提供了一个有价值的数据库，可以与这些卫星从我们周围的宇宙收集的光谱进行比较。

The different wavelengths of light emitted or absorbed by molecules - the molecular spectrum - encodes a wealth of information about the internal structure and the physics inherent to the species being observed. Each molecule's spectrum is unique, and can be used like a fingerprint to identify it. This property is powerful, especially so in astrophysics, since the only information we receive from remote stars, galaxies, and the interstellar medium comes from the light they produce or absorb.This proposal describes a program of research that records molecular spectra of species that have known or potential relevance to astrophsyics. Many of the molecules we study are quite unstable because they react with atmospheric gases and are quickly destroyed - but in space, where the density of matter is low, they persist for long times. We create these unstable molecules by stripping material from a rod housed in a vacuum chamber with a laser pulse. The hot plume of material then reacts with a fast-moving jet of helium gas entrained with stable reactant molecules like methane or methanol to produce the unstable species found in space. The jet is crossed with laser beams whose wavelengths can be continuously varied, and when the wavelength matches that of an absorption the molecule fluoresces, producing a signal that we can detect to map the spectrum. We specialize in molecules containing an atom of metal that comes from the rod, and is bonded to a ligand that comes from the reactant gas. Metal-bearing molecules like FeH and CrH; FeO, VO and TiO; and MgNC and MgCN have already been observed in the atmospheres of stars (including our sun). We will look for species like FeP, VP, and TiP which one day may be observed in space.The construction of the Canadian Light Source synchrotron in Saskatoon, SK has added an exciting new possibility for molecular spectroscopy experiments - access to intense and well-collimated light at very long wavelengths. The synchrotron light allows us to rapidly acquire spectra of extremely high quality in the difficult 2-30 terahertz region of the electromagnetic spectrum, where the fundamental vibrations of many larger molecules of astrophysical interest lie. Many currently-active satellite-borne instruments are sensitive to this region, and the data my students and I collect provides a valuable database for comparison with the spectra these satellites collect from the universe around us.