Darmstadt 2008 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 14: Cluster
MO 14.4: Vortrag
Donnerstag, 13. März 2008, 09:15–09:30, 3G
Pure rotational spectra of PbSe and PbTe: potential function, Born-Oppenheimer breakdown, field shift effect and magnetic shielding — Barbara M. Giuliano1, Luca Bizzocchi1, Stephen Cooke2, Deike Banser3, Mareike Hess3, Juliane Fritzsche3, and •Jens-Uwe Grabow3 — 1Universitá di Bologna, Dipartimento di Chimica "G. Ciamician", vie F. Selmi 2, 40126 Bologna, Italia — 2University of North Texas, Department of Chemistry, Denton, TX 76203, United States of America — 3Gottfried-Wilhelm-Leibniz-Universität, Institut für Physikalische Chemie & Elektrochemie, Lehrgebiet A, Callinstraße 3A, 30167 Hannover, Deutschland
We present the supersonic-jet Fourier-transform microwave spectra of 42 isotopologues of PbSe (16) and PbTe (26). Using our LASER-ablation jet source, vibrationally very highly excited states of up to v=13 could be prepared. A multi-isotopologue analysis yields precise spectroscopic constants and Born-Oppenheimer breakdown correction coefficients. A significant contribution to the Born-Oppenheimer break-down could be attributed to the finite size of the Pb nucleus, the so-called field-shift effect. From the magnetic hyperfine interaction in isotopologues containing dipolar nuclei the nuclear spin-rotation coupling constants and NMR shielding parameters were determined. Direct fits of a radial Hamiltonian yield analytic potential-energy and Born-Oppenheimer breakdown radial functions. Besides contributing to the understanding of the internuclear potential, electronic structure and chemical bond of intermetallic species, the study also demonstrates the wealth of information encoded in pure rotational spectra.