The overtone spectrum of C2D2 and C2H2 by ICLAS-VECSEL near 1 μm

The intracavity laser absorption spectra (ICLAS) of dideuteroacetylene, C2D2, and acetylene, C2H2, have been recorded between 1.03 and 0.99 mum with a vertical external cavity surface emitting laser (VECSEL) leading to the observation of seven and six bands, for C2D2 and C2H2 respectively, most of them newly reported. The strong nu(1) + 3nu(3) band of C2D2 at 9794.07cm(-1) is found accompanied by the two Pi-Pi hot bands with nu(4) = 1 and nu(5) = 1 lower state and by the nu(2) + 3nu(3) + 2nu(4) band near 9935 cm(-1). This last band results from an intensity transfer from the nu(1) + 3nu(3) band induced by the 1/244 anharmonic interaction. The nu(1) + 3nu(3) band of C-13(12) CD2, present in natural abundance in the sample, could also be detected at 9746.16 cm(-1) in full agreement with local mode model predictions. The different bands of both C2H2 and C2D2 were found mostly unperturbed and the spectroscopic parameters retrieved from the rovibrational analyses agree satisfactorily with the predictions of the respective effective Hamiltonian models. (C) 2003 Elsevier Science (USA). All rights reserved.