Knowledge Bank

High resolution Fourier transform spectra of monoisotopic $H280$Se have been recorded in the $2700-7000cm-1$ spectral domain and analysed leading to d precise set of experimental rotational levels for the (030), (110), (011), (120), (021), (200), (101), (002), (210), (111), (300), (201) and (102) vibrational states of this molecule. In order to fit these data to within their experimental uncertainty it proved necessary to consider explicitly the strong Coriolis and Darling-Dennsion interactions between the ($v1v2v3$) and ($v1-1v2v3+1$), and ($v1v2v3$) and ($v1-2v2v3+2$) vibrational states respectively as well as weaker interactions. In this way, the experimental levels were calculated to within their experimental uncertainty and precise vibrational energies, and rotational and coupling constants were derived for all the studied states. These results together with $those1,2$ concerning (000), (020), (100) and (001) were fit to obtain a set of equilibrium rotational constants and rotation-vibration interaction constants, and an improved equilibrium structure of the molecule has been obtained.