NASA Ames PAH IR Spectroscopic Database

Transitions

Frequency [wavenumbers]	Wavelength [microns]	Integrated cross-section [km/mol]
3055	3.273	126.4
1933	5.173	5.117
1917	5.216	2.047
1904	5.252	2.047
1836	5.446	1.023
1820	5.495	1.023
1800	5.555	3.07
1786	5.599	8.428
1731	5.777	1.023
1713	5.839	5.117
1686	5.933	4.094
1637	6.109	4.094
1573	6.356	3.07
1554	6.435	2.047
1546	6.467	2.047
1540	6.493	1.023
1474	6.784	1.023
1465	6.825	4.094
1416	7.062	2.047
1389	7.201	4.094
1338	7.474	5.117
1323	7.559	2.047
1299	7.699	8.428
1292	7.738	4.094
1288	7.761	2.047
1199	8.338	1.023
1165	8.581	2.047
1124	8.894	6.02
1054	9.485	1.023
997.1	10.03	7.224
953.6	10.49	8.428
933.4	10.71	2.047
895.3	11.17	84.28
766.7	13.04	1.023
742.9	13.46	102.3
627.7	15.93	1.023
607.7	16.46	2.047
551.6	18.13	11.44

Laboratory Spectrum

Lab — Left-clk & Shift: drag to zoom; Left-clk + Ctrl: Pan; Right-clk: Reset.

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.
Tetracene

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