FOURIER TRANSFORM INFRARED SPECTROSCOPY OF THE H$_2$F$^+$ $\nu_1$, $\nu_3$ AND $\nu_2$ BANDS

Abstract

Since HF is known as interstellar species, the protonated HF may exist with detectable abundance. Vibration-rotation spectra of H$_2$F$^+$ $\nu_1$ and $\nu_3$ bands were studied by infrared laser spectroscopy. The $\nu_2$ band and pure rotational spectra have not been reported. In this study, we report FTIR spectroscopy of H$_2$F$^+$ $\nu_1$, $\nu_3$ and $\nu_2$ bands. The ion was produced with hollow cathode discharge in F$_2$, He and H$_2$ mixture. A simultaneous analysis of FT data combined with laser spectroscopic data was curried out for $\nu_1$ and $\nu_3$ bands, to determine ground state molecular constants. Absorption lines in the $\nu_2$ region were assigned by using the ground state combination differences. Determined molecular constants can be used to predict pure rotational transition frequencies.