J/ApJ/825/96ivo://CDS.VizieR/J/ApJ/825/96doi:10.26093/cds/vizier.18250096CDSTsuge M.Bahou M.Wu Y.-J.Allamandola L.Lee Y.-P.2017-01-23T22:00:00Z2016-10-11T15:44:44ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.fratomic-physicsinfrared-astronomyspectroscopyThe mid-infrared emission from galactic objects, including reflection nebulae, planetary nebulae, proto-planetary nebulae, molecular clouds, etc, as well as external galaxies, is dominated by the unidentified infrared (UIR) emission bands. Large protonated polycyclic aromatic hydrocarbons (H^+^PAHs) were proposed as possible carriers, but no spectrum of an H^+^PAH has been shown to exactly match the UIR bands. Here, we report the IR spectrum of protonated ovalene (7-C_32_H_15_^+^) measured in a para-hydrogen (p-H_2_) matrix at 3.2K, generated by bombarding a mixture of ovalene and p-H_2_ with electrons during matrix deposition. Spectral assignments were made based on the expected chemistry and on the spectra simulated with the wavenumbers and infrared intensities predicted with the B3PW91/6-311++G(2d,2p) method. The close resemblance of the observed spectral pattern to that of the UIR bands suggests that protonated ovalene may contribute to the UIR emission, particularly from objects that emit Class A spectra, such as the IRIS reflection nebula, NGC 7023.2016ApJ...825...96Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/825/96CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/825/96https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/825/96http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/825/96https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/825/96https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/825/96http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/825/96GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfrareddefaultJ/ApJ/825/96/table2*Comparison of experimental observation with vibrational wavenumbers and IR intensities of 7-C_32_H_15_^+^ predicted with the B3PW91 methodf_Calc[f] Flag on Calc (2)meta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintModeVibrational mode numberphys.mol.qnSymSymmetry of vibrational modephys.atmol.parityp-H2Observed 7-C_32_H_15^+^ vibrational wavenumber (1)em.freqcharf_p-H2[e] Flag on p-H2 (2)meta.codecharCalcCalculated 7-C_32_H_15^+^ vibrational wavenumber (3)em.freqcharDesApproximate description (4)meta.notecharJ/ApJ/825/96/table3*Vibrational wavenumbers and relative IR intensities of 1-, 2-, and 3-C_32_H_15_^+^ predicted with the B3PW91/6-311++G(2d,2p) methodrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintModeVibrational mode number (1)phys.mol.qnSymSymmetry of vibrational modephys.atmol.parityWavenum-1[52/3073] Predicted wavenumber of 1-C_32_H_15_^+^cm**-1em.freqintNorm-1[0/100] Normalized value of Wavenumber-1 (2)phys.atmolintWavenum-2[53/3072] Predicted wavenumber of 2-C_32_H_15_^+^cm**-1em.freqintNorm-2[0/100] Normalized value of Wavenumber-2 (3)phys.atmolintWavenum-3[54/3071] Predicted wavenumber of 3-C_32_H_15_^+^cm**-1em.freqintNorm-3[0/100] Normalized value of Wavenumber-3 (4)phys.atmolint