Hot Band Spectroscopy of the Formyl Cation, H12C16O+

Abstract

Midinfrared spectra of the formyl cation, HCO(+), were recorded by direct absorption in a glow discharge (composition CO, 50 mTorr; H2, 50 mTorr; He, 7 Torr) using a color center laser spectrometer and velocity modulation with heterodyne detection. The bands measured were 10(0)0-00(0)0, 11(1)0-01(1)0, 12(0)0-02(0)0, 12(2)0-02(2)0, 10(0)1-00(0)1, 11(1)1-01(1)1, 20(0)0-10(0)0, and 10(0)2-00(0)2. These bands were analyzed and fitted together with all other available rotationally resolved spectra to arrive at a new set of spectroscopic constants for HCO(+). The relative intensities were fit to obtain a rotational temperature, Trot = 434 ± 7 K, and vibrational temperatures for each mode, T1 = 3300 ± 240 K, T2 = 841 ± 15 K, and T3 = 3157 ± 68 K.