High resolution FTIR spectroscopy of DCCCl: Anharmonic resonances in the nu(1) and nu(2) bands

High-resolution infrared spectra of the v(1) and v(2) bands of DCCCl were o bserved using Bruker IFS 120HR Fourier transform spectrometers at resolutio ns of 0.0044 and 0.0035 cm(-1), respectively. For the DCC35 Cl isotopomer, the v(1) as well as the v(2) band was found to be heavily perturbed. Detail ed analyses revealed that the v(1) state is in resonance with the l = 0 sub state of the + 4v(4) state and that the v(2) state is in resonance with the l = 0 substate of the v(3) + 4v(5) state. The rotational constants played a key role in identifying the perturbing states. In contrast, for the (DCCC l)-Cl-37 isotopomer, the rotational structures of the v(1) and v(2) states are almost regular but slightly perturbed by interactions with the v(3) + 4 v(5) and v(3) + 4(v5) states, respectively. The constants of resonances as well as the molecular constants for the v(1), v(2), v(3) + 4(v4) and v(3) 4v(5) states were determined. (C) 2001 Academic Press.