NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Infrared Spectra of Substituted Polycyclic Aromatic HydrocarbonsCalculations are carried out using density functional theory (DFT) to determine the harmonic frequencies and intensities of 1-methylanthracene, 9-methylanthracene, 9-cyanoanthracene, 2-aminoanthracene, acridine, and their positive ions. The theoretical data are compared with matrix-isolation spectra for these species also reported in this work. The theoretical and experimental frequencies and relative intensities for the neutral species are in generally good agreement, whereas the positive ion spectra are only in qualitative agreement. Relative to anthracene, we find that substitution of amethyl or CN for a hydrogen does not significantly affect the spectrum other than to add the characteristic methyl C-H stretch and C-N stretch (near 2200/cm), respectively. However, addition of NH2 dramatically affects the spectrum of the neutral. Not only are the NH2 modes themselves strong, but this electron withdrawing group induces sufficient partial charge on the ring to give the neutral molecule characteristics of the anthracene cation spectrum. The sum of the absolute intensities is about four times larger for 2-aminoanthracene than for 9-cyanoanthracene. Substituting nitrogen in the ring at the nine position (acridine) does not greatly alter the spectrum compared with anthracene.
Document ID
20020047557
Acquisition Source
Ames Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Bauschlicher, Charles W., Jr.
(NASA Ames Research Center Moffett Field, CA United States)
Langhoff, Stephen R.
(NASA Ames Research Center Moffett Field, CA United States)
Hudgins, Douglas M.
(NASA Ames Research Center Moffett Field, CA United States)
Sandford, Scott A.
(NASA Ames Research Center Moffett Field, CA United States)
Allamandola, Louis J.
(NASA Ames Research Center Moffett Field, CA United States)
Arnold, James O.
Date Acquired
August 20, 2013
Publication Date
January 1, 1997
Subject Category
Chemistry And Materials (General)
Funding Number(s)
PROJECT: RTOP 242-80-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available