Vibrational mode analysis of void induced coronene as a possible carrier
  of the astronomical aromatic infrared bands
  Void induced di-cation coronene C23H12++ is a possible carrier of the
astronomically observed polycyclic aromatic hydrocarbon (PAH). Based on density
functional theory, multiple spin state analysis was done for neutral void
coronene C23H12. Singlet spin state was most stable (lowest total energy). By
the Jahn-Teller effect, there occurs serious molecular deformation. Point group
D6h of pure coronene transformed to C2 symmetry having carbon two pentagons.
Advanced singlet stable molecules were di-cation C23H12++ and di-anion C23H12-
-. Molecular configuration was almost similar with neutral C23H12. However,
electric dipole moment of these two charged molecules show reversed direction
with 1.19 and 2.63 Debey. Calculated infrared spectrum of C23H12++ show a very
likeness to observed one of two astronomical sources of HD44179 and NGC7027.
Harmonic vibrational mode analysis was done for C23H12++. At 3.2 micrometer,
C-H stretching at pentagons was featured. From 6.4 to 8.7 micrometer, C-C
stretching mode was observed. In-plane-bending of C-H was in a range of 7.6-9.2
micrometer. Both C-H out-of plane bending and C-C stretching were accompanied
from 11.4 to 14.3 micrometer. Astronomically observed emission peaks of 3.3,
6.2, 7.6, 7.8, 8.6, 11.2, 12.7, 13.5 and 14.3 micrometer were compared well
with calculated peaks of 3.2, 6.5, 7.6, 7.8, 8.6, 11.4, 12.9, 13.5, and 14.4
micrometer.
