High-resolution infrared spectroscopy of 13C12CD2: the bending states with v4+v5 up to 3

The high-resolution infrared spectrum of deuterated acetylene containing one C-13 atom, (CCD2)-C-13-C-12, has been recorded by Fourier transform spectroscopy in the range 450-1700cm(-1). The upsilon(4) and upsilon(5) bending fundamental bands and a number of overtone, combination and hot bands were identified. In total, 3210 rotation vibration transitions were assigned to 27 bands involving bending states with both upsilon(4) + upsilon(5) and |l(4) + l(5)| up to 3. The ground state and 13 vibrationally excited states were characterised, i.e., all the l-vibrational components of the excited bending manifolds with upsilon(4) + upsilon(5) up to 2, ((II)pi), ((II)pi), and (pi and phi). Two simultaneous least-squares fits of all assigned transitions have been performed, one considering transitions with upsilon(4) + upsilon(5) up to 2, the other adding the transitions with upsilon(4) + upsilon(5) = 3. The model Hamiltonian adopted for the analysis takes into account the usual vibration and rotation l-type resonances within each vibrational manifold and the Darling-Dennison anharmonic resonance between and , and between and . Two sets of 33 and 42, respectively, spectroscopic parameters were derived. They reproduce 1512 and 2450 assigned transitions with root mean square values of 3.5 x 10(-4) and 3.9 x 10(-4) cm(-1), respectively. The transitions of four hot bands reaching the ((II)pi) state were fitted simultaneously to the effective upper state parameters.