Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014, Finland.
J Chem Phys. 2013 Nov 28;139(20):204303. doi: 10.1063/1.4832384.
Noble-gas hydrides HNgY (Ng is a noble-gas atom and Y is an electronegative group) are sensitive probes of local environment due to their relatively weak bonding and large dipole moments. We experimentally studied HXeBr in Ar, Kr, and N2 matrices, HXeCCH in Ne and N2 matrices, and HXeH in an N2 matrix. These are the first observations of noble-gas hydrides in an N2 matrix. An N2 matrix strongly increases the H-Xe stretching frequency of HXeBr and HXeCCH with respect to a Ne matrix, which is presumably due to a strong interaction between the HNgY dipole moment and quadrupole moments of the surrounding lattice N2 molecules. The spectral shift of HXeBr in an N2 matrix is similar to that in a CO2 matrix, which is a rather unexpected result because the quadrupole moment of CO2 is about three times as large as that of N2. The H-Xe stretching frequencies of HXeBr and HXeCCH in noble-gas matrices show a trend of ν(Ne) < ν(Xe) < ν(Kr) < ν(Ar), which is a non-monotonous function of the dielectric constants of the noble-gas solids. The MP2(full) calculations of HXeBr and HXeCCH with the polarizable continuum model as well as the CCSD(T) calculations of the HXeBr···Ng and HXeCCH···Ng (Ng = Ne, Ar, Kr, and Xe) complexes cannot fully explain the experimental observations. It is concluded that more sophisticated computational models should be used to describe these experimental findings.
稀有气体氢化物 HNgY（Ng 是一种稀有气体原子，Y 是一个电负性基团）由于其较弱的键合和较大的偶极矩，是探测局部环境的敏感探针。我们实验研究了 Ar、Kr 和 N2 基质中的 HXeBr、Ne 和 N2 基质中的 HXeCCH 以及 N2 基质中的 HXeH。这是首次在 N2 基质中观察到稀有气体氢化物。与 Ne 基质相比，N2 基质强烈增加了 HXeBr 和 HXeCCH 的 H-Xe 伸缩频率，这可能是由于 HNgY 偶极矩与周围晶格 N2 分子的四极矩之间存在强烈相互作用。N2 基质中 HXeBr 的光谱位移与 CO2 基质中的光谱位移相似，这是一个相当出人意料的结果，因为 CO2 的四极矩大约是 N2 的三倍。在稀有气体基质中，HXeBr 和 HXeCCH 的 H-Xe 伸缩频率表现出 ν(Ne) < ν(Xe) < ν(Kr) < ν(Ar)的趋势，这是非单调函数关系的稀有气体固体的介电常数。用极化连续体模型进行的 HXeBr 和 HXeCCH 的 MP2(full)计算以及 HXeBr···Ng 和 HXeCCH···Ng（Ng=Ne、Ar、Kr 和 Xe）复合物的 CCSD(T)计算都不能完全解释实验观测结果。因此，应该使用更复杂的计算模型来描述这些实验结果。
