Towards a comprehensive electronic database of polycyclic aromatic hydrocarbons and its application in constraining the identities of possible carriers of the diffuse interstellar bands.
A theoretical approach is developed to pre-select individual polycyclic aromatic hydrocarbons (PAHs) as possible carriers of the diffuse interstellar bands (DIBs). In this approach, a computer program is used to enumerate all PAH molecules with up to a specific number of fused benzene rings. Fast quantum chemical calculations are then employed to calculate the electronic transition energies, oscillator strengths, and rotational constants of these molecules. An electronic database of all PAHs with up to any specific number of benzene rings can be constructed this way. Comparison of the electronic transition energies, oscillator strengths, and rotational band contours of all PAHs in the database with astronomical spectra allows one to constrain the identities of individual PAHs as possible carriers of some of the intense narrow DIBs. Using the current database containing up to 10 benzene rings we have pre-selected 8 closed-shell PAHs as possible carriers of the famous lambda6614 DIB.
Tan
Xiaofeng
X
X Scientific, Inc., 1000 Kiely Boulevard Unit 90, Santa Clara, CA 95051, United States. x.tan@jhu.edu
D001555:Benzene Derivatives / Q000737:chemistry; D003198:Computer Simulation; D019443:Cosmic Dust / Q000032:analysis*; D016208:Databases, Factual / Q000639:trends*; D004526:Efficiency; D019418:Evolution, Chemical; D005118:Extraterrestrial Environment / Q000737:chemistry; D020407:Internet; D046911:Macromolecular Substances / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry* / Q000145:classification*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D019265:Spectroscopy, Near-Infrared / Q000379:methods
D001555:Benzene Derivatives; D019443:Cosmic Dust; D046911:Macromolecular Substances; D011084:Polycyclic Aromatic Hydrocarbons