Infrared chemiluminescence from the NO + HCO reaction: observation of the 2ν1−ν1 hot band of HNO

Infrared chemiluminescence in the 2200–3000 cm−1 range was observed from vibrationally excited HNO molecules produced in the reaction of NO with HCO. Formyl radicals were obtained from the OH + CH2O reaction in as reactor connected with a Fourier transform spectrometer. The HNO spectrum consists of Δν1 = −1 transitions from the (1ν2ν3) and (200) levels. The anharmonicity coefficient x11 = − 116±1 cm−1 was obtained from the position of the center of the (002)−(001) hot band, ν0 = 2452 cm−1.