title: Theoretical IR spectra of ionized naphthalene.
abstract: We report the results of a theoretical study of the effect of ionization on the IR spectrum of naphthalene, using ab initio molecular orbital theory.  For that purpose we determined the structures, band frequencies, and intensities of neutral and positively ionized naphthalene.  The calculated frequencies and intensities allowed an assignment of the most important bands appearing in the newly reported experimental spectrum of the positive ion.  Agreement with the experimental spectrum is satisfactory enough to take into consideration the unexpected and important result that ionization significantly affects the intensities of most vibrations.  A possible consequence on the interpretation of the IR interstellar emission, generally supposed to originate from polycyclic aromatic hydrocarbons (PAHs), is briefly presented.
authors.affiliation: Molecular Research Institute, Palo Alto, California 94304.
authors.forename: F
authors.initials: F
authors.lastname: Pauzat
authors.forename: D
authors.initials: D
authors.lastname: Talbi
authors.forename: M D
authors.initials: MD
authors.lastname: Miller
authors.forename: D J
authors.initials: DJ
authors.lastname: DeFrees
authors.forename: Y
authors.initials: Y
authors.lastname: Ellinger
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003198:Computer Simulation; D008962:Models, Theoretical; D009281:Naphthalenes / Q000032:analysis* / Q000737:chemistry*; D011083:Polycyclic Compounds / Q000032:analysis* / Q000737:chemistry; D013055:Spectrophotometry, Infrared
chemical_list: D009281:Naphthalenes; D011083:Polycyclic Compounds; C031721:naphthalene