We report 133 Cs NMR and 75 As Nuclear Quadrupole Resonance (NQR) measurements on the normal metallic state above Tc of a quasi-one-dimensional superconductor Cs2Cr3As3 (Tc < 1.6 K). From the 133 Cs NMR Knight shift 133 K measured at the Cs1 site, we show that the uniform spin susceptibility χspin increases from 295 K to ∼ 60 K, followed by a mild suppression; χspin then levels off below ∼10 K. In contrast, a vanishingly small magnitude of 133 K indicates that Cs2 sites contribute very little to electrical conduction and the exchange interactions between 3d electrons at Cr sites. Low frequency Cr spin dynamics, reflected on 75 As 1/T1T (the nuclear spin-lattice relaxation rate 1/T1 divided by temperature T ), shows an analogous trend as χspin. Comparison with the results of 1/T1T near Tc with K2Cr3As3 (Tc = 6.1 K) and Rb2Cr3As3 (Tc = 4.8 K) establishes a systematic trend that substitution of K + ions with larger alkali ions progressively suppresses Cr spin fluctuations together with Tc.

The origin of fatty acids on the prebiotic Earth is important as they likely formed the encapsulating membranes of the first protocells. Carbon-rich meteorites (i.e., carbonaceous chondrites) such as Murchison and Tagish Lake are well known to contain these molecules, and their delivery to the early planet by intense early meteorite bombardments constitutes a key prebiotic source. We collect the fatty acid abundances measured in various carbonaceous chondrites from the literature and analyze them for patterns and correlations. Fatty acids in meteorites include straight-chain and branchedchain monocarboxylic and dicarboxylic acids up to 12 carbons in length-fatty acids with at least 8 carbons are required to form vesicles, and modern cell membranes employ lipids with ∼12-20 carbons. To understand the origin of meteoritic fatty acids, we search the literature for abiotic fatty acid reaction pathways and create a candidate list of 11 reactions that could potentially produce these fatty acids in meteorite parent bodies. Straight-chain monocarboxylic acids (SCMA) are the dominant fatty acids in meteorites, followed by branched-chain monocarboxylic acids (BCMA). SCMA are most abundant in CM2 and Tagish Lake (ungrouped) meteorites, ranging on average from 10 2 ppb to 4×10 5 ppb, and 10 4 ppb to 5×10 6 ppb, respectively. In CM, CV, and Tagish Lake meteorites, SCMA abundances generally decrease with increasing carbon chain length. Conversely, SCMA abundances in CR meteorites peak at 5 and 6 carbons in length, and decrease on either side of this peak. This unique CR fatty acid distribution may hint at terrestrial contamination, or that certain fatty acid reactions mechanisms are active in different meteorite parent bodies (planetesimals). We identify Fischer-Tropsch-type synthesis as the most promising pathway for further analysis in the production of fatty acids in planetesimals.