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Theoretical Study of the Electronic Spectra of a Polycyclic Aromatic Hydrocarbon, Naphthalene, and its DerivativesIn order to preselect possible candidates for the origin of diffuse interstellar bands observed, semiempirical quantum mechanical method INDO/S was applied to the optical spectra of neutral, cationic, and anionic states of naphthalene and its hydrogen abstraction and addition derivatives. Comparison with experiment shows that the spectra of naphthalene and its ions were reliably predicted. The configuration interaction calculations with single-electron excitations provided reasonable excited state wavefunctions compared to ab initio calculations that included higher excitations. The degree of similarity of the predicted spectra of the hydrogen abstraction and derivatives to those of naphthalene and ions depends largely on the similarity of the it electron configurations. For the hydrogen addition derivatives, very little resemblance of the predicted spectra to naphthalene was found because of the disruption of the aromatic conjugation system. The relevance of these calculations to astrophysical issues is discussed within the context of these polycyclic aromatic hydrocarbon models. Comparing the calculated electronic energies to the Diffuse Interstellar Bands (DIBs), a list of possible candidates of naphthalene derivatives is established which provides selected candidates for a definitive test through laboratory studies.
Document ID
19970037278
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Du, Ping
(Molecular Research Inst. Palo Alto, CA United States)
Salama, Farid
(NASA Ames Research Center Moffett Field, CA United States)
Loew, Gilda H.
(Molecular Research Inst. Palo Alto, CA United States)
Date Acquired
August 17, 2013
Publication Date
January 1, 1993
Publication Information
Publication: Chemical Physics
Publisher: Elsevier Science Publishers B. V.
Volume: 173
ISSN: 0301-0104
Subject Category
Chemistry And Materials (General)
Report/Patent Number
NAS 1.26:204913
NASA-CR-204913
Accession Number
97N72503
Funding Number(s)
CONTRACT_GRANT: NCC2-733
Distribution Limits
Public
Copyright
Public Use Permitted.
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