Photochemical Evolution of Alanine in Association with the Martian Soil Analog Montmorillonite: Insights Derived from Experiments Conducted on the International Space Station.

The (PSS) experiment was part of the European Space Agency's mission and was conducted on the International Space Station from 2014 to 2016. The PSS experiment investigated the properties of montmorillonite clay as a protective shield against degradation of organic compounds that were exposed to elevated levels of ultraviolet (UV) radiation in space. Additionally, we examined the potential for montmorillonite to catalyze UV-induced breakdown of the amino acid alanine and its potential to trap the resulting photochemical byproducts within its interlayers.

Infrared Spectroscopy and Photochemistry of Anthracoronene in Cosmic Water Ice.

We present a laboratory study of the polycyclic aromatic hydrocarbon (PAH) anthracoronene (AntCor, CH) in simulated interstellar ices in order to determine its possible contribution to the broad infrared absorption bands in the 5-8 μm wavelength interval. The Fourier transform infrared (FTIR) spectrum of AntCor, codeposited with water ice, was collected. The FTIR spectrum of the sample irradiated with ultraviolet photons was also collected.

Infrared Spectroscopy of Matrix-Isolated Neutral and Ionized Anthracoronene in Argon.

The matrix-isolated mid-IR (MIR) spectrum of neutral and ionized anthracoronene (CH, AnthCor) in argon has been measured experimentally, compared to the spectrum of its parent molecules, coronene and anthracene, and analyzed by comparison to a theoretical spectrum computed using density functional theory (DFT). The experimental and theoretical band positions generally agree within 0-10 cm. Anthracoronene exhibits extremely intense cation and anion bands around 1330 and 1318 cm.

Photochemistry of coronene in cosmic water ice analogs at different concentrations.

This work presents the photochemistry of ultraviolet (UV) irradiated coronene in water ices at 15 K, studied using mid-infrared Fourier transform (FTIR) spectroscopy for CH:HO at concentrations of (1:50), (1:150), (1:200), (1:300) and (1:400). Previous UV irradiation studies of anthracene:HO, pyrene:HO and benzo[ghi]perylene:HO ices at 15 K have shown that aromatic alcohols and ketones, as well as CO and HCO are formed at very low temperatures. Like-wise, here, in addition to the coronene cation, hydroxy-, keto-, and protonated coronene (coronene-H) are formed.

Infrared spectroscopy of matrix-isolated neutral polycyclic aromatic nitrogen heterocycles: The acridine series.

The matrix-isolated, mid-infrared spectra of seven acridine-based polycyclic aromatic nitrogen heterocycles (PANHs) have been measured and compared to their non-nitrogen containing parent molecule. The acridine species investigated include acridine, benz[a]acridine, benz[c]acridine, dibenz[a,j]acridine, dibenz[c,h]acridine, dibenz[a,h]acridine and dibenz[a,c]acridine. The previously reported results for 1 and 2-azabenz[a]anthracenes are included for comparison.