The absorption spectrum of acetylene in the 2ν2 + 3ν3 region. A test of the cluster model

Three new weak bands of 12C2H2 at 13473.69, 13493.87 and 13787.97 cm−1 have been recorded by intracavity laser absorption spectroscopy and rotationally analyzed. Their presence was anticipated, on the basis of the cluster model recently presented by Abbouti Temsamani and Herman. The band energies and upper rotational parameters are well reproduced. The comparison between predicted and observed relative band intensities, including those previously reported in the literature in the range investigated, is briefly discussed.