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Title:INFRARED SPECTRA OF PROTONATED QUINOLINE (1-C9H7NH+) IN SOLID PARA-HYDROGEN
Author(s):Tseng, Chih-Yu
Contributor(s):Lee, Yuan-Pern
Subject(s):Astronomy
Abstract:Large protonated polycyclic aromatic hydrocarbons (H$^{+}$PAH) and polycyclic aromatic nitrogen heterocycles (H$^{+}$PANH) have been proposed as possible carriers of unidentified infrared (UIR) emission bands from galactic objects. The nitrogen atom in H$^{+}$PANH is expected to induce a blue shift of the C=C stretching band near 6.2 $mu$m so that their emission bands might agree with the UIR band better than those of H$^{+}$PAH._x000d_ _x000d_ In this work, we report the IR spectrum of protonated quinoline and its neutral species measured upon electron bombardment during deposition of a mixture of quinoline and textsl{para}-hydrogen at 3.2 K. New features were assigned to 1-chem{C_9H_7NH}$^{+}$ and 1-chem{C_9H_7NH}, indicating that the protonation and hydrogenation occur at the N-atom site. The intensities of features of 1-chem{C_9H_7NH}$^{+}$ diminished when the matrix was maintained in darkness for 10 h, whereas those of 1-chem{C_9H_7NH} increased. Spectral assignments were made according to comparison of experimental results with anharmonic vibrational wavenumbers and IR intensities calculated with the B3LYP/6-311++G(d,p) method. Although agreement between the observed spectrum of 1-chem{C_9H_7NH}$^{+}$ and the UIR emission bands is unsatisfactory, presumably because of the small size of quinoline, we did observe C=C stretching bands at 1641.4, 1598.4, 1562.0 wn, blue-shifted from those at 1618.7, 1580.8, 1510.0 wn of the corresponding protonated PAH (C$_{10}$H$_{9}$$^{+}$), pointing to the direction of the UIR bands._x000d_
Issue Date:6/21/2017
Publisher:International Symposium on Molecular Spectroscopy
Citation Info:APS
Genre:CONFERENCE PAPER/PRESENTATION
Type:Text
Language:English
URI:http://hdl.handle.net/2142/96806
DOI:10.15278/isms.2017.WA12
Date Available in IDEALS:2017-07-27


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