Knowledge Bank

Expressions have been derived for the Dunham coefficients $Y01$ and $Y10$ (in terms of $Be$, $\omega e$, and other molecular parameters) after allowing for the breakdown of the Born-Oppenheimer approximation. It has been shown that the corrections resulting from the breakdown of the Born-Oppenheimer approximation are of the same order of magnitude as the corrections for anharmonicity (the so-called “Dunham corrections”). The determination of $Be$ from precise $Y01$ values is discussed with application to the molecules $H7$ and CO.