THE INFRARED AND UV-VISIBLE SPECTRA OF POLYCYCLIC AROMATIC HYDROCARBONS CONTAINING (5, 7)-MEMBER RING DEFECTS: A THEORETICAL STUDY

Journal Article · Sun May 20 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/751/1/3· OSTI ID:22037280

Huagen, Yu; Nyman, Gunnar ^[1]

---

1. Department of Chemistry and Molecular Biology, Physical Chemistry, University of Gothenburg, SE-412 96 Gothenburg (Sweden)

We report a theoretical investigation of the infrared (IR) spectra of polycyclic aromatic hydrocarbons (PAHs) containing (5, 7)-member ring defects based on a C{sub 48}H{sub 18} model. Calculations are mostly performed using the hybrid B3LYP density functional theory (DFT) with a 6-31G(d) or 4-31G basis set. The results show that the Stone-Wales defect in PAHs can yield a strong IR band at 1448 cm{sup -1} and a weak band at 611 cm{sup -1}, which may contribute to the UIR (unidentified infrared) bands at 6.9 {mu}m and 16.4 {mu}m observed in the interstellar medium. The charge effect on the IR spectra is discussed. The stability of the ring defected PAHs is also addressed by exploring the minimum energy pathway on the potential energy surface and through their UV-visible spectra, which are computed using a TDDFT method.

• OSTI ID: 22037280
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 751; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
DENSITY FUNCTIONAL METHOD
INFRARED SPECTRA
MOLECULES
POLYCYCLIC AROMATIC HYDROCARBONS
POTENTIAL ENERGY
STABILITY
SURFACES
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA