Darr Joshua P, Crowther Andrew C, Loomis Richard A, Ray Sara E, McCoy Anne B
Department of Chemistry, Washington University, One Brookings Drive, CB 1134, Saint Louis, Missouri 63130, USA.
J Phys Chem A. 2007 Dec 27;111(51):13387-96. doi: 10.1021/jp076465u. Epub 2007 Dec 4.
The dependence of the long-range interactions between molecular hydrogen and iodine monochloride on the geometry between the molecules is investigated. Laser-induced fluorescence and action spectroscopy experiments have identified multiple conformers of the o,p-H2...I35,37Cl(X,v' '=0) van der Waals complexes. A conformer with the hydrogen molecule localized at the iodine end of the dihalogen, most likely with C2v symmetry, is significantly more stable than an asymmetric conformer with the hydrogen localized in the well oriented orthogonally to the I-Cl bond axis, D0' ' = 186.4(3) cm-1 versus 82.8(3) <or= D0' ' <or= 89.6(3) cm-1. Complexes containing the o-H2(j=1) species are more strongly bound than those with p-H2(j=0). The electronically excited o,p-H2...I35Cl(A,v') and o,p-H2...I35,37Cl(B,v') complexes are found to have preferred asymmetric structures with binding energies bracketed between 73.7-80.5 and 69.5-76.3 cm(-1) for o-H2... I35Cl(A,v'=23) and o-H2...I35Cl(B,v'=3), respectively. Calculations of the H2...I35Cl(B,v'=3) intermolecular vibrational energies and probability amplitudes undertaken using a scaled He + ICl(B,v'=3) potential enable us to make tentative assignments of the excited-state levels experimentally accessed.
研究了分子氢与一氯化碘之间长程相互作用对分子间几何构型的依赖性。激光诱导荧光和光声光谱实验已确定了邻位、对位 -H₂...I³⁵,³⁷Cl(X, v'' = 0)范德华复合物的多种构象体。氢分子位于二卤化物碘端的一种构象体，很可能具有C₂v对称性，比氢位于与I-Cl键轴正交取向良好位置的不对称构象体稳定得多，其D₀'' = 186.4(3) cm⁻¹，而82.8(3) ≤ D₀'' ≤ 89.6(3) cm⁻¹。含有邻位 -H₂(j = 1)物种的复合物比含有对位 -H₂(j = 0)的复合物结合更强。发现电子激发态的邻位、对位 -H₂...I³⁵Cl(A, v')和邻位、对位 -H₂...I³⁵,³⁷Cl(B, v')复合物具有优先的不对称结构，对于邻位 -H₂...I³⁵Cl(A, v' = 23)和邻位 -H₂...I³⁵Cl(B, v' = 3)，其结合能分别在73.7 - 80.5和69.5 - 76.3 cm⁻¹之间。使用缩放的He + ICl(B, v' = 3)势对H₂...I³⁵Cl(B, v' = 3)分子间振动能量和概率振幅进行的计算，使我们能够对实验观测到的激发态能级进行初步归属。
