High-resolution FTIR spectrum of the ν5 band of HCOOD

The high-resolution Fourier transform infrared spectrum of HCOOD has been measured in the nu(5) region between 1120 and 1220 cm(-1) with a resolution of 0.004 cm(-1). As expected for an in-plane vibrational fundamental mode, the nu(5) band is a hybrid band consisting of both a-type and b-type transitions. Using the Watson's A-reduced Hamiltonian in the Gamma representation, 1943 infrared transitions have been assigned and fitted to give 12 rovibrational constants for the upsilon(5) = 1 state. The nu(5) band is primarily A type with a band center at 1177.09378 +/- 0.00002 cm(-1). It is found that nu(5) is slightly perturbed by the nearby 2 nu(7). About 90 perturbed transitions were identified. (C) 1998 Academic Press.