THE ABSORPTION-SPECTRUM OF (C2H2)-C-12 BETWEEN 12,800 AND 18,500 CM(-1) .2. ROTATIONAL ANALYSIS

The rotational structure of the vibrational bands of (C2H2)-C-12 is in vestigated in three spectral energy regions not previously systematica lly explored at high resolution, 12 800-13 500 cm(-1), 14 000-15 200 c m(-1) and 16 500-18 360 cm(-1), on the basis of new spectral data reco rded by intracavity laser absorption spectroscopy. The rotational anal ysis of 17 new absorption bands arising from the ground state is repor ted (11 Sigma(u)(+)-Sigma(g)(+) bands and 6 Pi(v)-Sigma(g)(+) bands). Four bands in the range studied show strong perturbations affecting bo th the line positions and intensities. Their detailed analysis is perf ormed in order to determine the nature of the coupling schemes, the vi brational species and the rotational constants of the perturber states . Altogether, the vibration-rotation parameters of 21 newly observed v ibrational states are derived.