L. Bizzocchi, C. Degli Esposti, L. Dore
Rovibrational bands between closely lying bending vibrational states of normal diacetylene and its bideuterated variant have been recorded in the submillimetre-wave region using a source-modulation spectrometer. The two isotopologues were produced by pyrolysis (1200?C) of benzene or benzene-d 6 vapour in a flow reactor. Measurements of the ?8 - ?6 band and of its ?9-associated hot band have been extended up to 615 and 420 GHz, respectively. Rotational and vibrational l-type resonance were taken into account in the analysis of the ?8 + ?9 - ?6 - ?9 band; in addition the cubic anharmonic resonance existing between the v 8 = v 9 = 1 state and the v 3 = 1 stretching state has been considered explicitly in the least-squares fits to the observed frequencies. Very accurate values of the band origins and of numerous spectroscopic constants have been determined for both isotopologues.
vibration: rotation: bands - diacetylene - hot: bands - pyrolysis - resonances
Volume 108, Number 18, Page 2315