The rotational spectra of GeS and GeSe were measured in the frequency range of 66 GHz to 110 GHz with high precision. The breakdown of the Born-Oppenheimer approximation was observed for the rotational constant yol. With the known molecular 37-factor and the electric dipole moment the adiabatic part of the Born-Oppenheimer correction can be extracted from the primary observation on y01. The adiabatic correction is very similar in both molecules but differs from the results in the earlier measurements on PbS.
The rotational microwave spectrum of PbS was measured in a frequency range from 65 to 105 GHz in order to determine the higher order isotopic effect of the rotational constant. From this we deduce (by calculating the nonadiabatic and the Dunham-correction) the adiabatic correction of the Born-Oppenheimer approximation, which depends linearly on the reciprocals of the masses of the two atoms in a diatomic molecule. Because of the small mass variation by isotopic substitution for the heavier molecules of the IV/VI-compounds the relative accuracy of the primary measurements must be of the order of 10 -6 . The least square fit of 112 rotational transitions yields a relative error of 10 -7 for the rotational constant y01 . The adiabatic corrections from Pb and S differ by a factor of 50, which was unexpected.Da die Masse der Elektronen gegenüber der der Nukleonen sehr viel kleiner ist und beide Teilchensorten sich in gleichartigen Coulomb-Feldern bewegen, kann man in 1. Näherung die Kerne als ruhend gegenüber den Elektronen ansehen und die Elektronenbewegung separiert von der Kernbewegung behandeln. Diesen Ansatz beinhaltet die Born-Oppenheimer Näherung 1 . Mit der Dunham-Potentialfunktion erhält man die bekannte Dunham-Formel 2 für die Energieeigenwerte der Rotationsschwingungszustände eines zweiatomigen Moleküls:
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.