NASA Ames PAH IR Spectroscopic Database

Transitions

Frequency [wavenumbers]	Wavelength [microns]	Integrated cross-section [km/mol]
3395	2.945	912.7
3062	3.266	39.99
3012	3.32	16.16
2830	3.534	425.5
2724	3.672	79.69
2665	3.752	114.4
2635	3.795	269.9
2601	3.844	100.5
2360	4.236	6710
2248	4.449	5768
2054	4.868	328.2
2026	4.936	10.94
2006	4.985	114.2
1982	5.046	7.306
1969	5.078	12.99
1892	5.285	54.8
1842	5.428	112.4
1740	5.745	149.1
1688	5.924	211.3
1660	6.025	98.44
1514	6.607	1950
1440	6.944	1821
1377	7.264	292
1369	7.303	216.7
1334	7.497	412.9
1315	7.603	277
1298	7.706	1104
1258	7.948	132.6
1211	8.26	3848
1125	8.891	96.18
1098	9.106	48.79
1083	9.231	86.57
1052	9.503	83.38
1039	9.626	93.55
1029	9.716	64.85
997.8	10.02	55.58
919.1	10.88	5232
873.5	11.45	6440
835.1	11.97	765.8
814.4	12.28	1716
779.6	12.83	5018
746.3	13.4	6717
739.1	13.53	66.36
734.5	13.61	88.6
715.8	13.97	7109
707	14.14	19.04
696	14.37	164.9
656.3	15.24	341
629.7	15.88	37.29
618.4	16.17	358.1

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.
Dibenzo[hi,uv]hexacene or dinaptho-pyrene
This species has known electronic transitions in the IR, see referenced work for details

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