Wang Xuefeng, Andrews Lester, Fang Zongtang, Thanthiriwatte K Sahan, Chen Mingyang, Dixon David A
Department of Chemistry, Box 400319, University of Virginia , Charlottesville, Virginia 22904-4319 United States.
Chemistry Department, Tongji University , Shanghai 200093, China.
J Phys Chem A. 2017 Mar 2;121(8):1779-1796. doi: 10.1021/acs.jpca.6b12607. Epub 2017 Feb 20.
The reactions of laser-ablated lanthanide metal atoms with hydrogen peroxide or hydrogen plus oxygen mixtures have been studied experimentally in a solid argon matrix and theoretically with the ab initio MP2 and CCSD(T) methods. The Ln(OH) and Ln(OH) molecules and Ln(OH) cations are the major products, and the reactions to form those hydroxides are predicted to be highly exothermic at the CCSD(T) level. Vibronic interactions are hypothesized to contribute to the abnormalities in deuterium shifts for Ln-OH(D) stretching modes for several hydroxides, consistent with CASSCF calculations. Additional new absorptions were assigned as HLnO or LnOH and OLnOH molecules. The tetrahydroxides of Ce, Pr, and Tb have also been observed. These reactive intermediates were identified from their matrix infrared spectra by using DO, HD, D, O, and O isotopic substitution, by matching observed frequencies with values calculated by electronic structure methods, and by following the trends observed in frequencies going through different lanthanide metal hydroxide series across the periodic table. The lanthanides are in the +II oxidation state for Ln(OH) and are in the +III oxidation state for Ln(OH) and Ln(OH).
已在固体氩基质中通过实验研究了激光烧蚀的镧系金属原子与过氧化氢或氢气加氧气混合物的反应，并使用从头算MP2和CCSD(T)方法进行了理论研究。Ln(OH)和Ln(OH)分子以及Ln(OH)阳离子是主要产物，并且预测在CCSD(T)水平下形成这些氢氧化物的反应是高度放热的。据推测，振动电子相互作用导致几种氢氧化物的Ln-OH(D)伸缩模式的氘位移异常，这与CASSCF计算结果一致。额外的新吸收峰被归属于HLnO或LnOH以及OLnOH分子。还观察到了Ce、Pr和Tb的四氢氧化物。通过使用DO、HD、D、O和O同位素取代，将观察到的频率与通过电子结构方法计算的值进行匹配，并遵循在整个周期表中不同镧系金属氢氧化物系列中观察到的频率趋势，从它们的基质红外光谱中识别出这些反应中间体。对于Ln(OH)，镧系元素处于+II氧化态，而对于Ln(OH)和Ln(OH)，镧系元素处于+III氧化态。
