Abstract book - Prof. Per Jensen, Ph.D. - Bergische Universität ...

86 Poster session, D39Low-energy vibrational modes of some naphthalene derivativesMarie-Aline Martin-Drumel 1,2 , Olivier Pirali 1,2 , Yohan Loquais 1,a , Cyril Falvo 1 ,Philippe Bréchignac 11 Institut des Sciences Moléculaires d’Orsay, CNRS, Université Paris XI, France;2 SOLEIL Synchrotron, AILES beamline, France, marie-aline.martin@synchrotronsoleil.frMartin-Drumel M.-A.Pirali O.Loquais Y.Falvo C.Brechignac P.FIR Fourier transform absorption spectra of several naphthalene derivatives have beenrecorded in the gas phase, yielding to an accurate determination of wavenumberposition for their low lying vibrational modes. Azulene (C 10 H 8 ), quinoline (C 9 H 7 N),isoquinoline (C 9 H 7 N), biphenyl (C 12 H 10 ), bibenzyl (C 13 H 12 ), diphenylmethane (C 14 H 14 )and 2-, 3-, 4-phenyltoluene (C 13 H 12 ) have been chosen for their close molecularstructure with naphthalene.Density functional calculations were carried out at the harmonic and anharmonic levelsto study the vibrational spectrum of the electronic ground state of these naphthalenederivatives and compare it to the parent molecule. Comparison between the calculatedand experimental vibrational frequencies indicates that B97-1/6-311G(d,p) frequencydetermination is reliable for the study of such compounds.Furthermore, the comparative study of three low-frequency vibrational modes of thesecompounds has revealed a significant influence of the skeletal structure on the FIRspectra. In consequence, since the FIR spectral range allows to distinguish moleculeswithin a family, this spectral region appears particularly interesting for preliminarysearches of these compounds in the interstellar medium.Fig. 1: FIR spectrum of azulene and comparison with B97-1/6-311G(d,p) anharmonicfrequency calculation.aNow at: IRAMIS, Centre d’études Nucléaires de Saclay, France