Knowledge Bank

The Fourier Transform infrared spectrum of $CHF3$ has been obtained between 1000 and $2000cm-1$ with a resolution of $0.005cm-1$ in the region $1110-1250cm-1$, three bands are to be considered, namely $\nu 2$ at $1141cm-1$, $\nu 5$ at 1158 and $\nu 3+\nu 6$ at $1208cm-1$. The two former are interacting through an X--Y type Coriolis resonance. The last one is affected by a very strong $\ell$(2,2) resonance, as it was the case in $\nu 6$. Moreover $\nu 5$ and $\nu 3+\nu 6$ are linked by a Fermi interaction. We shall explain how it was possible to assign transitions among this extremely dense Spectrum of about 6000 lines. Preliminary molecular constants will also be given.