Diode Laser Spectrum of HCCCN: CN Stretching Band

Abstract

Abstract The ν2 vibration-rotation band of cyanoacetylene. HCCCN, has been studied by diode laser spectroscopy in the wavenumber region from 2240 cm-1 to 2290 cm-1. In addition to the fundamental band we have assigned hot bands arising from v7 = 1. 2. and 3 states and from v6 = 1 state. In these hot bands splittings due to l-type doubling and l-type resonance were clearly observed. The transition wavenumbers were measured precisely, with an estimated error of 0.001 cm-1. Their analysis simultaneously with the microwave data allowed an accurate determination of the band origin v0 = 2273.99539(11) cm-1, the rotational constant B′ = 4527.4861 (28) MHz. and the centrifugal distortion constant D′ = 0.53547(43) kHz.