McDonald D C, Mauney D T, Leicht D, Marks J H, Tan J A, Kuo J-L, Duncan M A
Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA.
Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, 44801 Bochum, Germany.
J Chem Phys. 2016 Dec 21;145(23):231101. doi: 10.1063/1.4972581.
Ion-molecule complexes of the form HAr are produced in pulsed-discharge supersonic expansions containing hydrogen and argon. These ions are analyzed and mass-selected in a reflectron spectrometer and studied with infrared laser photodissociation spectroscopy. Infrared spectra for the n = 3-7 complexes are characterized by a series of strong bands in the 900-2200 cm region. Computational studies at the MP2/aug-cc-pVTZ level examine the structures, binding energies, and infrared spectra for these systems. The core ion responsible for the infrared bands is the proton-bound argon dimer, Ar-H-Ar, which is progressively solvated by the excess argon. Anharmonic vibrational theory is able to reproduce the vibrational structure, identifying it as arising from the asymmetric proton stretch in combination with multiple quanta of the symmetric argon stretch. Successive addition of argon shifts the proton vibration to lower frequencies, as the charge is delocalized over more ligands. The Ar-H-Ar core ion has a first solvation sphere of five argons.
HAr形式的离子 - 分子复合物是在含有氢气和氩气的脉冲放电超声速膨胀中产生的。这些离子在反射式光谱仪中进行分析和质量选择，并通过红外激光光解离光谱进行研究。n = 3 - 7复合物的红外光谱在900 - 2200 cm区域具有一系列强吸收带。在MP2/aug - cc - pVTZ水平上的计算研究考察了这些体系的结构、结合能和红外光谱。负责红外吸收带的核心离子是质子键合的氩二聚体Ar - H - Ar，它被过量的氩逐步溶剂化。非谐振动理论能够重现振动结构，将其确定为由不对称质子伸缩与对称氩伸缩的多个量子组合产生。随着氩的连续添加，质子振动频率降低，因为电荷在更多配体上离域。Ar - H - Ar核心离子有一个由五个氩组成的第一溶剂化层。
