High resolution laser spectroscopy of small gas-phase metal-containing molecules

该研究项目旨在利用激光光谱学了解小的气相金属配体分子的基本结构和性质。分子通过各种方法产生，用激光激发到高能态，然后通过发光从高能态衰减回低能级。通过探测发射的光或观察分子吸收辐射的能量，可以对分子中的键合、结构和相互作用有详细的了解。例如，这些信息对于理解发生在大气、空间以及任何表面化学或催化过程中的化学和物理过程都很重要。所使用的主要实验技术在冷分子束（定义明确的分子流）中产生分子，以获得高度分辨和简化的光谱。在实验中，高功率激光聚焦在脉冲气体喷嘴前的金属目标上。来自目标的汽化原子与混合在从喷嘴流出的惰性气体中的试剂分子发生反应。然后气体通过一个小孔膨胀进入真空系统，产生光束。用高分辨率可调谐激光对分子进行下游探测，并观察到分子吸收作为频率的函数。研究的目标分子有两组：A)双原子含金属物种（DMCs）和B)小金属含多原子物种（MCPs）。我们将测量一些dmc（如RuF， RuP, RuH），这些分子的吸收将首次被观察到，以全面研究键合特征，并为某些催化和天体物理学感兴趣的分子提供光谱信息。我们感兴趣的是具有天体物理学重要性或对理解催化和化学吸附很重要的mcp。我们最近研究了MgCCH/C4H， CaCCH/CCD, Ca/SrOCH3，并将从MgOCH3， SiCCH， AlCCH和FeCCH开始寻找这类新分子。另一种重要的MCP是金属单羰基。这些分子在表面化学和催化反应中具有重要意义，但对它们的气相研究却很少。我们将首次研究这些mcp，以提供有关其特性的新信息。预计在未来五年内，该研究项目将培养至少10名本科生和4名研究生成为HQP。技术和团体培训将为每个学生提供宝贵的、多方面的经验，为他们在大学、研究机构、政府机构和行业中担任专业职位做好准备。

The research program is geared towards understanding the fundamental structure and properties of small, gas-phase, metal-ligand molecules using laser spectroscopy. The molecules are produced by various methods and excited with a laser to higher energy states from which they can decay back to lower energy levels by emitting light. By detecting either this emitted light or observing at which energy the molecules absorb the radiation, a detailed understanding of the bonding, structure and interactions in the molecules can be gained. This information is important, for example, in understanding both the chemical and physical processes occurring in the atmosphere, in space, and in any surface chemistry or catalytic process.The primary experimental technique used produces molecules in cold molecular beams (well defined streams of molecules) to give highly resolved and simplified spectra. In the experiments, a high power laser is focussed onto a metal target held in front of a pulsed gas nozzle. Vaporized atoms from the target react with reagent molecules mixed in the inert gas flowing from the nozzle. The gases then expand through a small hole into a vacuum system creating the beam. The molecules are probed downstream with a high resolution tunable laser and molecular absorptions are observed as a function of frequency.Two groups of molecules are targeted in the research: A) diatomic metal-containing species (DMCs), and B) small metal-containing polyatomics (MCPs). We will measure a number of DMCs (e.g. RuF, RuP, RuH), where absorptions for these molecules will be observed for the first time, to comprehensively study the bonding characteristics and provide spectral information for certain molecules of catalytic and astrophysical interest. We are interested in MCPs which have astrophysical importance or are important for understanding catalysis and chemisorptions. We have recently studied MgCCH/C4H, CaCCH/CCD, Ca/SrOCH3, and will search for new molecules of this type starting with MgOCH3, SiCCH, AlCCH and FeCCH. Another MCP species of importance are metal monocarbonyls. Few gas-phase studies of these molecules, which are important in surface chemistry and catalytic reactions, exist. We will examine these MCPs for the first time to provide new information on their properties.It is anticipated that a minimum of ten undergraduate students and four graduate students will be trained as HQP in this research program over the next five years. Technical and group training will provide each student with valuable and versatile experiences that will prepare them to take up professional positions in universities, research institutes, government agencies, and industry.