EXCITED VIBRATIONAL-STATES OF BENZENE - HIGH-RESOLUTION FTIR SPECTRA AND ANALYSIS OF SOME OUT-OF-PLANE VIBRATIONAL FUNDAMENTALS OF C6H5D

We have measured the infrared spectra of the nu(4), nu(10b) and nu(11) fundamental bands of C6H5D in the range 540-830 cm(-1) with an instru mental bandwidth of 0.0024 cm(-1) (unapodized FWHM) using a Bomem DA 0 02 Interferometric Fourier Transform spectrometer. The rotational anal ysis for nu(4) yields ground state constants by combining ground state combination differences and published microwave data (M. Oldani and A . Bauder, Chem. Phys. Lett. 108 (1984) 7). Excited state constants for the nu(4) level were obtained up to quartic terms, using Watson's A-r eduction Hamiltonian in the IIIr representation, resulting in a band c enter <(nu)over tilde>(0)(4)=697.593 cm(-1). A partial analysis is pre sented for the nu(10b) fundamental (<(nu)over tilde>(0)(10b)=778.027 c m(-1)), which appears to be locally perturbed by the nu(16a) + nu(16b) combination band. The very strong nu(11) band is strongly perturbed, most probably by nu(6a) and nu(6b) The results are discussed in relati on to comparison with accurate ab initio electronic structure calculat ions including non Born-Oppenheimer effects as well as potential appli cations with isotope tracer detection and infrared laser chemistry. (C ) 1997 Elsevier Science B.V.