NASA Ames PAH IR Spectroscopic Database

Transitions

Frequency [wavenumbers]	Wavelength [microns]	Integrated cross-section [km/mol]
3071	3.256	126.4
1947	5.137	3.371
1603	6.239	0.3371
1598	6.258	0.8428
1530	6.536	1.686
1505	6.646	7.826
1460	6.847	12.04
1448	6.907	0.4214
1436	6.963	0.59
1431	6.99	1.686
1428	7.005	0.8428
1419	7.047	0.8428
1351	7.4	0.8428
1303	7.675	3.371
1246	8.027	9.03
1224	8.171	0.5057
1203	8.315	2.528
1165	8.581	1.686
1144	8.74	2.528
1094	9.137	1.686
1040	9.616	5.057
1002	9.975	1.686
948.2	10.55	2.528
877.6	11.39	1.686
864.9	11.56	10.23
833	12	1.686
812.8	12.3	58.39
735	13.61	84.28
710.2	14.08	3.371
617.5	16.19	5.057
494	20.24	3.371

Laboratory Spectrum

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This spectrum was measured using the matrix isolation technique. Samples are prepared by co-deposition of the PAH in the gaseous state with an overabundance of argon onto a cold CsI window suspended in a high vacuum chamber (p ~ 10-8 mtorr). The CsI window temperature is held between 10 and 15 K for the duration of the experiment. The infrared spectrum of the cold CsI window is recorded prior to (I₀) and immediately after sample deposition (I_n). The absorbance spectrum for a neutral, matrix isolated PAH is log(I_n/I₀).

By irradiating this matrix with ultraviolet radiation from a microwave powered hydrogen discharge lamp produces ionized PAHs. The infrared spectrum is again measured (I_i), now having absorption bands due to both the neutral and ionized PAH. This absorbance spectrum (log (I/I_i)) is compared with that of the neutral PAH. Most of the new bands produced by ultraviolet irradiation are due to the ionized form of the PAH. See the provided reference for the specific details regarding the data presented here. In some cases a few bands near 1600 cm^-1 may be due to H₂O.

Note(s):

The reported total integrated absorption cross-section for the CH_str band located around 3000 cm^-1 (3.3 μm) was established by disregarding any substructure seen in the band and simply integrating the entire feature, including any close-by bands.
Phenanthrene

You are kindly asked to consider the following references for citation when using the database:

C.W. Bauschlicher, Jr., A. Ricca, C. Boersma, L.J. Allamandola, "THE NASA AMES PAH IR SPECTROSCOPIC DATABASE: COMPUTATIONAL VERSION 3.00 WITH UPDATED CONTENT AND THE INTRODUCTION OF MULTIPLE SCALING FACTORS", The Astrophysical Journal Supplement Series, 234, 32, 2018 10.3847/1538-4365/aaa019 — BibTeX - RIS
C. Boersma, C.W. Bauschlicher, Jr., A. Ricca, A.L. Mattioda, J. Cami, E. Peeters, F. Sánchez de Armas, G. Puerta Saborido, D.M. Hudgins, and L.J. Allamandola, "THE NASA AMES PAH IR SPECTROSCOPIC DATABASE VERSION 2.00: UPDATED CONTENT, WEBSITE AND ON/OFFLINE TOOLS", The Astrophysical Journal Supplement Series, 211, 8, 2014 10.1088/0067-0049/211/1/8 — BibTeX - RIS
Mattioda, A. L., Hudgins, D. M., Boersma, C., Ricca, A., Peeters, E., Cami, J., Sánchez de Armas, F., Puerta Saborido, G., Bauschlicher, C. W., J., and Allamandola, L. J. "THE NASA AMES PAH IR SPECTROSCOPIC DATABASE: THE LABORATORY SPECTRA", The Astrophysical Journal Supplement Series, 251, 22, 2020 10.3847/1538-4365/abc2c8 — BibTeX - RIS