J/ApJ/825/96 IR spectrum of protonated ovalene (7-C32H15+) (Tsuge+, 2016)
The infrared spectrum of protonated ovalene in solid para-hydrogen and
its possible contribution to interstellar unidentified infrared emission.
Tsuge M., Bahou M., Wu Y.-J., Allamandola L., Lee Y.-P.
<Astrophys. J., 825, 96-96 (2016)>
=2016ApJ...825...96T 2016ApJ...825...96T (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Spectra, infrared
Keywords: astrochemistry; infrared: ISM; ISM: lines and bands; ISM: molecules
Abstract:
The 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-C32H15+)
measured in a para-hydrogen (p-H2) matrix at 3.2K, generated by
bombarding a mixture of ovalene and p-H2 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.
Description:
Absorption spectra spanning 450-5000cm-1 were recorded with a
Fourier-transform infrared spectrometer (Bomem, DA8) equipped with a
KBr beamsplitter and a HgCdTe detector cooled to 77K. See section 2
for further details.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 94 170 *Comparison of experimental observation with vibrational
wavenumbers and IR intensities of 7-C32H15+
predicted with the B3PW91 method
table3.dat 37 135 *Vibrational wavenumbers and relative IR intensities of
1-, 2-, and 3-C32H15+ predicted with
the B3PW91/6-311++G(2d,2p) method
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Note on table2.dat and table3.dat: Geometrical optimization and harmonic
vibrational analysis were performed with the B3PW91 (Becke's three-parameter
hybrid exchange functional and Perdew/Wang correlation functional) method
(Becke 1993JChPh..98.5648B 1993JChPh..98.5648B; Perdew et al. 1996PhRvB..5416533P 1996PhRvB..5416533P). The standard
split valence 6-31G(d,p) and 6-311++G(2d,2p) basis sets were used.
See section 2 for further explanations.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Mode Vibrational mode number
17- 20 A4 --- Sym Symmetry of vibrational mode
22- 38 A17 --- p-H2 Observed 7-C32H_15+ vibrational wavenumber (1)
40 A1 --- f_p-H2 [e] Flag on p-H2 (2)
42- 51 A10 --- Calc Calculated 7-C32H_15+ vibrational wavenumber (3)
53 A1 --- f_Calc [f] Flag on Calc (2)
55- 94 A40 --- Des Approximate description (4)
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Note (1): Relative intensities are listed in parentheses. For lines that could
not be integrated accurately due to severe interference, approximate
intensities, s (strong), m (medium), or w (weak) are given.
Note (2): Flag as follows:
e = Tentative assignments
f = Anharmonic wavenumbers calculated at the B3PW91/6-31G(d,p)
level of theory.
Note (3): Scaling factors 0.958 and 0.978 were used for regions above and below
2500cm-1, respectively. The predicted IR intensities are
normalized to 312.8km/mol.
Note (4):
ip = in-plane;
oop = out-of-plane.
g = Involving H atoms at the 14-position.
h = Involving H atoms at the 5-, 6-, 8-, and 9-positions.
i = Involving H atoms at all positions excluding the 5- and 9-positions.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Mode Vibrational mode number (1)
8- 9 A2 --- Sym Symmetry of vibrational mode
11- 14 I4 cm-1 Wavenum-1 [52/3073] Predicted wavenumber of 1-C32H15+
16- 18 I3 --- Norm-1 [0/100] Normalized value of Wavenumber-1 (2)
20- 23 I4 cm-1 Wavenum-2 [53/3072] Predicted wavenumber of 2-C32H15+
25- 27 I3 --- Norm-2 [0/100] Normalized value of Wavenumber-2 (3)
29- 32 I4 cm-1 Wavenum-3 [54/3071] Predicted wavenumber of 3-C32H15+
34- 37 I4 --- Norm-3 [0/100] Normalized value of Wavenumber-3 (4)
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Note (1): Scaling factors 0.958 and 0.978 were used for regions above and below
2500cm-1, respectively.
Note (2): Normalized to that of v19 (201.9km/mol).
Note (3): Normalized to that of v20 (180.1km/mol).
Note (4): Normalized to that of v19 (300.9km/mol).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 29-Aug-2016