Radiation-Driven Destruction of Thiophene and Methyl-Substituted Thiophenes.

Thiophene and two derivatives (2-methylthiophene and 3-methylthiophene) have been detected on the surface of Mars with the Sample Analysis at Mars instrument suite onboard NASA's Curiosity rover. Thiophene could serve as a secondary chemical biosignature since the secondary biosynthesis of thiophene is considered an important production pathway. However, it is critical to understand the abiotic formation and destruction of thiophene and its derivatives since these pathways could affect the molecules' stabilities on planetary surfaces over geological timescales.

Infrared intensities of methyl acetate, an interstellar compound - comparisons of three organic esters.

The mid-infrared (IR) spectra of the simplest aliphatic esters have been studied in the past in the solid, liquid, and gas phases with an emphasis on vibrational frequencies and peak assignments. However, relatively little has been published on the IR intensities of the amorphous forms of these compounds. These IR intensities are of particular interest to the astrochemical community as they are needed to help quantify laboratory measurements of the formation and destruction of extraterrestrial molecules, including esters.

Infrared Spectral Intensities of Amine Ices, Precursors to Amino Acids.

Here, we address the paucity of infrared (IR) spectral data needed to quantify low-temperature experiments with amine ices, such as the formation of amino acids, by reporting new IR results on solid phases of methylamine (CHNH) and ethylamine (CHCHNH), precursors to glycine and alanine, respectively. Mid-IR band strengths and absorption coefficients for CHNH and CHCHNH, in both amorphous and crystalline forms, are presented, along with measurements of a density and refractive index (670 nm) for each. For these same compounds, we also have calculated IR optical constants, and they are being made available in electronic form.

Infrared band strengths and other properties of amorphous and crystalline dimethyl ether.

Laboratory astrochemists have generated infrared (IR) data for nearly all common classes of organic compounds, but ethers in the solid phase continue to be neglected despite detections of ethers in the interstellar medium by radio astronomers and uncertainty in how extraterrestrial ethers are formed. To address this paucity of data, here we present new mid-IR spectra of amorphous and crystalline dimethyl ether, (CH)O, the simplest member of its class. Spectral positions are tabulated and compared to previous results, but more importantly we also report IR band strengths and absorption coefficients, which we have not found in the literature and on which quantitative IR studies depend.