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MO: Fachverband Molekülphysik

MO 2: Theory: Quantum Chemistry and Molecular Dynamics

MO 2.8: Talk

Monday, March 14, 2011, 12:15–12:30, MER 02

Theory corroborates experiment: a relativistic study of the isotopic field shift in rotational spectra — •Stefan Knecht¹ and Trond Saue² — ¹Institut for Fysik og Kemi, Syddansk Universitet, Odense, Danmark — ²Laboratoire de Physique Quantique, CNRS/Université Paul Sabatier, Toulouse, France

A number of distinctive molecular properties such as the nuclear magnetic resonance shielding parameters, Mössbauer isomer shifts and isotopic field shift probe the electronic density near the nuclei. Their appealing feature is that they provide local information at a nuclear center with great sensitivity to the chemical environment.

Here, we present accurate theoretical estimates of the isotopic field shift in rotational spectra of lead chalcogenides PbX (X=S,Se,Te) and thallium halides TlY (Y=F,Cl,Br,I) derived from 4-component relativistic Coupled-Cluster and Density Functional Theory calculations. We compare our findings [1] with the early experimental work [2,3] on this correction term to the Dunham coefficient Y₀₁, which is due to a finite nuclear charge distribution, as well as with other theoretical predictions [4]. It is highlighted that a sophisticated relativistic approach is required to achieve an excellent agreement with the experiment.

[1] S. Knecht and T. Saue, in preparation (2010).
[2] J. Schlembach and E. Tiemann, Chem. Phys. 68 (1982) 21.
[3] H. Knöckel, T. Kröckertskothen, and E. Tiemann, Chem. Phys. 93 (1985) 349.
[4] K. C. Etchison, C. T. Dewberry, and S. A. Cooke, Chem. Phys. 342 (2007) 71.