FTIR spectrum of the ν3 band of HCOOD

The Fourier transform infrared spectrum of the monodeuterated isotopic species of formic acid, HCOOD, measured with a resolution of 0.004 cm(-1) has been studied in the region of the nu(3) fundamental band centered at 1772 cm(-1). In addition, IR transitions in the 7(1) --> 5(1)7(1) and 9(1) --> 5(1)9(1) hot bands have been found and assigned in the region of the nu(5) band, which was previously measured with a resolution of 0.003 cm(-1). This enabled us to increase significantly the number of experimental data. In the course of the investigation, the band centers and the rotational, centrifugal distortion, and interaction parameters of the 3(1), 5(1)7(1), and 5(1)9(1) coupled vibrational states have been determined. The total numbers of transitions assigned and included in the fit were 2193 for the nu(3) band, 602 for the nu(5) + nu(7) combination band, and 657 and 516 for the 7(1) --> 5(1)7(1) and 9(1) --> 5(1)9(1) hot bands. The standard deviation of the fit was 0.000283 cm(-1). The values obtained for the band origins are 1772.119(24) cm(-1) for nu(3), 1732.084(24) cm(-1) for nu(5) + nu(7), and 1680.962939(64) cm(-1) for nu(5) + nu(9). (C) 2002 Elsevier Science (USA).