High-Resolution Infrared Spectrum of nu5, nu4, nu3, nu4 + nu5, and 2nu4 Band Systems of Deuterobromoacetylene.

High-resolution vibration-rotation spectra of gas-phase deuterobromoacetylene have been recorded in the 240-990 cm-1 infrared region. The analyzed band systems are rich in hot bands and have a high density of lines. Five band systems and a total of 124 vibration-rotation bands of the isotopic species DCC79Br and DCC81Br have been rotationally analyzed. Accurate rotational parameters and vibrational wavenumbers for 33 vibrational states of each species have been obtained from the rotational analysis. l doubling and rotational l resonance have been observed on some states and the respective resonance parameters have been obtained through nonlinear least-squares optimization. A Fermi resonance block model with perturbation terms has been used for the analysis of the vibrational states. With optimized parameters, the model produces root-mean-square deviations of observed - calculated wavenumbers of about 0.3 cm-1 for both isotopic species. Copyright 1999 Academic Press.