NASA Ames PAH IR Spectroscopic Database

Transitions

Frequency [wavenumbers]	Wavelength [microns]	Integrated cross-section [km/mol]
3061	3.267	138.5
1932	5.176	1.023
1923	5.199	4.094
1916	5.22	2.047
1904	5.253	2.047
1893	5.282	2.047
1860	5.378	6.02
1792	5.58	2.047
1726	5.794	11.44
1673	5.976	1.023
1602	6.242	4.094
1527	6.547	2.047
1518	6.588	1.023
1449	6.901	13.24
1422	7.032	1.023
1416	7.062	6.02
1395	7.17	8.428
1350	7.407	5.117
1343	7.448	22.27
1303	7.675	7.224
1259	7.942	1.023
1207	8.287	7.224
1187	8.425	1.023
1155	8.655	1.023
1149	8.702	3.07
1133	8.828	6.02
1093	9.146	1.023
1088	9.193	1.023
1036	9.65	2.047
968.3	10.33	1.023
897.9	11.14	2.047
851.8	11.74	1.023
846.3	11.82	102.3
815.5	12.26	18.66
776.8	12.87	5.117
770.9	12.97	25.28
755.8	13.23	30.7
648.9	15.41	14.45
570	17.54	2.047
544.2	18.38	9.03
512.5	19.51	7.224

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.
Benzo[g,h,i]perylene

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