贵金属硫化物低电子态激光诱导荧光光谱研究

It is well known that the noble metal sulfides and hydrosulfides are widely used in mineral, synthesis, catalysis, fuel cell and biological sciences. However, among all of the noble metal sulfides, only AuS and AuS2 molecules have been experimentally studied in the gas phase by the photoelectron spectroscopy (PES). The few experimental works greatly limited the understanding of the electronic structures and their potential applications. The development of the new techniques, such as high-resolution laser, supersonic molecule beam, laser ablation and laser induced fluorescence (LIF), had made it possible to study those unstable molecules, including the free radicals. .Experimentally, the noble metal sulfides and hydrosulfides molecules can be created by the DALAS source, which combines supersonic molecule beam jet, laser ablation and high voltage pulsed discharge. The newly invented SYNC-LIF technology will be used to identify the desired molecular fluorescence from noisy emission background of variuos particals which are generated during laser ablation and discharge processes. High-resolution LIF spectroscopy will study the electronic transitions among the low-energy electronic states, and provide detailed spectroscopic information which plays important role in understanding how the 4d/5d electrons of transition metal atom are bonded with 3p valence electrons from sulfur atom. The expected spectroscopic information will not only increase the knowledge about the electronic structures of the noble metal sulfide , but also be a benchmark for quantum chemistry computations about the spectroscopy and dynamics of the noble metal inorganic species..The motivation of this work is to experimentally study the electronic structures of the noble metal sulfides and hydrosulfides, which are bound by metal atom (Ru~Ag/Os~Au) with sulfur-containing groups (-S/-SH), by accurately measuring the vibrational and rotational energy levels in the low-energy electronic states with LIF spectroscopy. The concerted experimental and quantum chemistry computational study will allow a complete understanding of the equilibrium geometries, electronic structures, and chemical bonding in these systems.

贵金属硫化物分子（贵金属原子Ru~Ag/Os~Au结合含硫基团-S/-SH）在地质矿产、合成、催化和生物科学等领域有着广泛的应用前景。然而，直到目前对于贵金属硫化物电子态结构的谱学研究工作非常稀少，极大的限制了对其电子态结构的理解以及潜在的可能应用的认识。本申请，结合激光溅射和超声射流分子束脉冲放电装置（DALAS源），产生贵金属硫化物气相分子，利用新建成的高灵敏、高分辨的激光诱导荧光光谱（LIF）实验装置，研究其电子基态和低能量激发态结构。实验精确测量贵金属硫化物的振动/转动分辨的紫外-可见光谱，通过光谱分析，确定各电子态的对称性，获得分子在不同电子态的转动常数、振动频率等光谱常数，键长、键角等几何构型，电子态中自旋轨道耦合等各种相互作用的类型及强度等，给出分子电子态势能面特征的信息。结合并对比量子化学计算结果，进一步加深对贵金属硫化物低电子态结构的理解。

项目拟计划利用激光光谱对贵金属硫化物分子（贵金属原子Ru~Ag/Os~Au结合含硫基团-S/-SH）进行研究，对多d电子的过渡金属元素化合物的低能量复杂电子结构进行深入理解。依托基金支持，我们搭建了激光光谱实验平台，包括：激光溅射和超声射流分子束脉冲放电装置（DALAS源）、分子离子产物飞行时间-质谱仪、自由基分子激光诱导荧光光谱仪，完成了Cu2、CuS和CuO等自由基分子的激光光谱实验测量工作、ZnS自由基测试性实验、AuO自由基的激光光谱测量测试性实验，尤其是CuO自由基大范围高分辨激光光谱的实验研究，帮助我们比较全面的理解过渡金属化合物复杂电子结构，并为进一步的同族Au元素化合物研究提供了重要参考。实验证明：DALAS源可以有效产生适用于激光光谱测量的气相金属化合物自由基分子，利用飞行时间质谱可以检测分子离子，利用激光诱导荧光光谱可以研究自由基的低能量激发态电子结构，实现了气相金属化合物自由基的产生、诊断、质谱分析、光谱测量等一套完整的实验过程。由于激光光谱实验平台搭建难度大、实验周期长，实验还需要更多时间和经验积累去探索贵金属硫化物自由基的电子态结构。