The gas-phase infrared spectra of phenanthrene-h(10) and phenanthrene-d(10)

The IR spectra of phenanthrene-h(10) and -d(10) have been recorded in the vapour phase from 200 to 3200 cm(-1) with a resolution of 0.2 cm(-1), using a multipass cell heated at 90 degrees C. The assignment of the vibrational bands has been performed by comparison with the theoretical spectra, evaluated using Density Functional Theory and Scaled Quantum Mechanical (SQM) force fields. We found that both methods reproduce the sequence of the experimental frequencies to a good accuracy, allowing in most cases consistent and unambiguous assignments. The relative intensities have also been measured and compared with theory. (C) 1997 Elsevier Science B.V.