The rotational spectra of205TI19F and203TI19F, molecular constants and break-down of the Born-Oppenheimer approximation

Research paper by J. Hoeft, K. P. R. Nair

Indexed on: 01 Dec '87Published on: 01 Dec '87Published in: Zeitschrift für Physik D Atoms, Molecules and Clusters


At wavelengths near 1 mm three rotational transitions of205Tl19F and203Tl19F have been observed. The analysis including previous measurements on rotational transitions at larger wavelengths resulted in sets of the Dunham coefficientsY01,Y11,Y21,Y31,Y02,Y12, andY03 of the two isotopic species. With these microwave data the constantsY10 ≈ ωe and −Y20 ≈ ωe xe were determined. The parameters of the Dunham potentiala0,a1,a2,a3,Be andre are given. The Dunham coefficientsYmn with the smallest relative experimental error show deviations from the general mass relations between isotopic species indicating a violation of the Born-Oppenheimer approximation.