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MO: Fachverband Molekülphysik
MO 2: Theory: Quantum Chemistry and Molecular Dynamics
MO 2.1: Vortrag
Montag, 14. März 2011, 10:30–10:45, MER 02
Range-separated density functional theory: a 4-component relativistic study of the rare gas dimers He2, Ne2, Ar2, Kr2, Xe2, Rn2, Uuo2 — •Ossama Kullie1 and Trond Saue2 — 1Institute de Quantique Chimie, Uni Strasbourg, 4, rue de Blais Pascal, 67000 Strasbourg, France. — 2Laboratoire de Chimie et Physique Quantiques, Université de Toulouse 3 (Paul Sabatier). Toulouse, France.
In this work we propose to apply range separation DFT or short-range DFT long-range wave function to calculate the spectroscopic constants of the ground states of the rare gas dimers and compare it with the DFT and MP2 results, with the literature and experimental values as far as are available.
We use in our work three now well known approximation, short-rang LDA long-range MP2 (srLDA-MP2) and short-rang PBE long-range MP2 (srPBE-MP2). The best result is obtained for srLDA-MP2 and the lighter dimers He2-Kr2.
For the heavy dimers Xe2 and Rn2 and the super-heavy member of the group Uuo2 we obtain good result for the bond length Re and the vibrational frequencies but srLDA-MP2 and MP2 both underestimate the bond energy for these dimers. The trend of the result from He2 to Xe2 in comparison with the experiment for srLDA-MP2, MP2 and DFT, let us give a conclusion about the reliability of the values of Rn2 and Uuo2 for which no experimental values are available and we recommend calculated values for the spectroscopic constants of these dimers.
[1] A relativistic ab initio electronic structure program. Release DIRAC10, (2010), http://dirac.chem.vu.nl.