Collect. Czech. Chem. Commun.
2005, 70, 797-810
https://doi.org/10.1135/cccc20050797
Theoretical Study of H2...I- van der Waals Anion Complex
Michal Ilčina, Vladimír Lukešb, Viliam Laurincb,* and Stanislav Biskupiča
a Department of Physical Chemistry, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava, Slovak Republic
b Department of Chemical Physics, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava, Slovak Republic
Abstract
The ab initio potential energy surface (PES) for the weak interaction of hydrogen molecule with iodine anion is presented. The surface was obtained by the supermolecular method at the MP4(SDTQ) level of theory. Our calculations indicate the van der Waals (vdW) system for the linear configuration at rH-H = 0.752 Å and R = 3.76 Å with a well depth of De = 2096 μEh. The presented PES reveals also a transition state for the perpendicular arrangement at rH-H = 0.7416 Å and R = 4.63 Å with an interaction energy of -113 μEh. The physical origin of stability of the vdW H2...I- structure with respect to the H2...X- (X = F, Cl, Br) one was analysed by the symmetry adapted perturbation theory (SAPT) based on the single determinant HF wave function. The separation of the interaction energy shows that the dispersion forces play a much more important role for the systems with Cl, Br and I than for H2...F- and their importance slightly increases in the order Cl < Br < I. The global importance of the electrostatic and the induction energies decreases in the order F > Cl > Br > I.
Keywords: Halogen anion complexes; Hydrogen; Iodine anion; van der Waals complex; Interaction energy; Potential energy surface; Intermolecular perturbation theory; SAPT.
References: 38 live references.
