UV/Vis+ photochemistry database: Structure, content and applications

Abstract

The "science-softCon UV/Vis⁺ Photochemistry Database" (www.photochemistry.org) is a large and comprehensive collection of EUV-VUV-UV-Vis-NIR spectral data and other photochemical information assembled from published peer-reviewed papers. The database contains photochemical data including absorption, fluorescence, photoelectron, and circular and linear dichroism spectra, as well as quantum yields and photolysis related data that are critically needed in many scientific disciplines. This manuscript gives an outline regarding the structure and content of the "science-softCon UV/Vis⁺ Photochemistry Database". The accurate and reliable molecular level information provided in this database is fundamental in nature and helps in proceeding further to understand photon, electron and ion induced chemistry of molecules of interest not only in spectroscopy, astrochemistry, astrophysics, Earth and planetary sciences, environmental chemistry, plasma physics, combustion chemistry but also in applied fields such as medical diagnostics, pharmaceutical sciences, biochemistry, agriculture, and catalysis. In order to illustrate this, we illustrate the use of the UV/Vis⁺ Photochemistry Database in four different fields of scientific endeavor.

Keywords: Database; Photochemistry; Radiative transfer; Spectroscopy; UV/Vis.

Fig. 1.

UV absorption spectrum of COF₂ obtained by Noelle [9] (blue curve), Noelle et al. [10] (red curve), and Molina and Molina [11] (green squares).

Fig. 2.

Linear dichroism absorbance spectrum of dibenzo-p-dioxin [12]. The absorbance curves were recorded with the electric vector of the sample beam parallel (blue line) and perpendicular (orange) to the stretching direction of the polyethylene polymer.

Fig. 3.

Degradation rate estimation (a) and product prediction (b) for direct photolysis of trifluralin.

Fig. 4.

Left: Absorptions due to molecules that are now commonly measured from space in the nadir geometry; Right: Back scattered albedo spectra from GOME measurements for two extreme examples. The highest albedo scene, corresponding to full coverage by high clouds, is white and quite bright, due to the cloud reflectance; the lowest albedo case is a cloud-free scene over the ocean [30].

Fig. 5.

Tropospheric NO₂ retrieved from SCIAMACHY measurements in the 425–450 nm spectral region. Pollution on urban scales is readily measured globally [30].

Fig. 6.

Absorption cross-section of benzene [40]: in the VUV region the cross-section values are between 2 and 3 orders of magnitude larger than in the UV range.

Fig. 7.

Example of SPICAM transmittance spectra obtained during one solar occultation observation. The color indicates to altitude probed from low altitudes (blue) to high altitudes (red). Black lines are fitted spectra using (Eq. (2)) [Figure from [42]].