High-Resolution FTIR Spectrum of the ν5Band of HCOOD☆

Abstract The high-resolution Fourier transform infrared spectrum of HCOOD has been measured in the ν 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 ν 5 band is a hybrid band consisting of both a -type and b -type transitions. Using the Watson's A -reduced Hamiltonian in the I r representation, 1943 infrared transitions have been assigned and fitted to give 12 rovibrational constants for the v 5 = 1 state. The ν 5 band is primarily A type with a band center at 1177.09378 ± 0.00002 cm −1 . It is found that ν 5 is slightly perturbed by the nearby 2ν 7 . About 90 perturbed transitions were identified.