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Your search keyword '"Ellinger, Y."' showing total 19 results
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19 results on '"Ellinger, Y."'

4. About the presence of arsenic in prebiotic species

Author

Ellinger Y., Toulouze M., Pilmé J., and Pauzat F.

Subjects
Microbiology, QR1-502, Physiology, QP1-981, Zoology, QL1-991
Abstract

The recent publication that some bacteria could use arsenic instead of phosphorus for building their DNA triggered a large controversy in the astro/exobiology community. Most comments claim that such a substitution is not possible. Here, we address the same question of the presence of As in DNA from a pure theoretical point of view, beyond any biological consideration. By means of “First principle“ quantum calculations we found that there is no energetical or structural argument to reject the As to P substitution in the DNA helix. However, a topological analysis of the electron density shows that As-DNA is much more fragile and most probably will not survive because it lacks the covalent bonds that insure the stability of biological P-DNA.

Published
2014
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5. Homochirality in space – Selective enrichment of chiral molecules on chiral surfaces

Author

Marloie G., Pauzat F., Ellinger Y., Markovits A., and Pilmé J.

Subjects
Microbiology, QR1-502, Physiology, QP1-981, Zoology, QL1-991
Abstract

Life on Earth, as we know it to day, is inseparable from homochirality. The presence of an enantiomeric excess in carbonaceous chondrites is well documented; among the different hypotheses considered to explain this undisputed fact, we chose to investigate the possibilities open by a selective adsorption on a chiral surface that would engage a process of enantiomeric enrichment. The chiral surface is that of the α-quartz { 10 10¯ } $\left\{ {10\,\overline {10} } \right\}$ and the chiral molécule is lactic acid, HOCH(CH3)COOH. In this theoretical work we rely on numerical simulations based on Density Functional Theory (DFT) that proved efficient in the super-molecule and periodic approaches to this category of phenomena. In view of the different types of adsorption sites, a statistical treatment was necessary; it shows that (S)-lactic acid is preferentially adsorbed with a selectivity of ~0.7 kcal/mol with respect to the (R) isomer.

Published
2014
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8. Formation of amines: hydrogenation of nitrile and isonitrile as selective routes in the interstellar medium

Author

Nguyen, T, Fourre, I, Favre, C., Barois, C., Congiu, E., Baouche, S., Guillemin, J-C, Ellinger, Y., Dulieu, F., Nguyen, T, Fourre, I, Favre, C., Barois, C., Congiu, E., Baouche, S., Guillemin, J-C, Ellinger, Y., and Dulieu, F.

Abstract

Context. Beyond NH3, only one primary alkylamine, CH3NH2, has been identified in the interstellar medium and the reason why is still not understood: its formation could occur in the gas phase or in icy environments. Aims. To consider any possible difference between the formation of primary and secondary amines, we studied the hydrogenation processes of CH3CN and CH3NC, which would lead to the simple primary CH3CH2NH2 and secondary CH3NHCH3 amines, respectively. Methods. Experimentally, the hydrogenation of CH3CN and CH3NC was carried out under ultra-high vacuum, using two beamlines to inject the nitrile/isonitrile and H onto substrate surfaces of gold or water ice. The reactions were monitored using infrared spectroscopy and the products were followed by mass spectrometry. Theoretically, the energetics of the hydrogenation paths were determined using the M06-2X functional after benchmarking against post Hartree-Fock procedures. Meanwhile, a survey of the high-mass star forming region W51/e2 has been performed. Results. Following co-deposition of CH3CN and H, we show that these species do not react together between 10 and 60 K. For CH3NC we found that the hydrogenation process works all the way through the CH3NHCH3 end product; we also identified the CH3NCH2 intermediate together with side products, CH4 and HCN, showing that the isonitrile backbone is breaking. These results are consistent with the calculations of a high barrier on the first hydrogenation step for CH3CN and a lower barrier for CH3NC. Conclusions. The formation of CH3CH2NH2 by hydrogenation of CH3CN appears rather unlikely in both the gas phase and ice environment whereas that of CH3NHCH3 is a clear possibility. The limiting factor appears to be the efficiency of the tunneling effect through the first activation barrier on the reaction paths. More surveys are required for further insight into the search for amines.

Published
2019

15. Differential adsorption of complex organic molecule isomers on interstellar ice surfaces

Author

Bertin, M., primary, Michaut, X., additional, Lattelais, M., additional, Mokrane, H., additional, Pauzat, F., additional, Pilmé, J., additional, Minot, C., additional, Ellinger, Y., additional, Romanzin, C., additional, Jeseck, P., additional, Fillion, J.-H., additional, Chaabouni, H., additional, Congiu, E., additional, Dulieu, F., additional, Baouche, S., additional, and Lemaire, J.-L., additional

Published
2012
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17. Differential adsorption of complex organic molecules isomers at interstellar ice surfaces

Author

Lattelais, M., primary, Bertin, M., additional, Mokrane, H., additional, Romanzin, C., additional, Michaut, X., additional, Jeseck, P., additional, Fillion, J.-H., additional, Chaabouni, H., additional, Congiu, E., additional, Dulieu, F., additional, Baouche, S., additional, Lemaire, J.-L., additional, Pauzat,, F., additional, Pilmé, J., additional, Minot, C., additional, and Ellinger, Y., additional

Published
2011
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19. DIFFERENTIAL ADSORPTION OF COMPLEX ORGANIC MOLECULE ISOMERS ON INTERSTELLAR ICE SURFACES.

Author

Bertin, M., Michaut, X., Lattelais, M., Mokrane, H., Pauzat, F., Pilme, J., Minot, C., Ellinger, Y., Romanzin, C., Jeseck, P., Fillion, J.-H., Chaabouni, H., Congiu, E., Dulieu, F., Baouche, S., and Lemaire, J.-L.

Subjects
ADSORPTION (Chemistry), ISOMERS, THERMODYNAMICS, ACETIC acid, INTERSTELLAR medium, ASTROPHYSICS, HYDROGEN bonding
Abstract

We present a combined theoretical and experimental study of the adsorption of two pairs of organic isomers, (i) acetic acid AA (CH3COOH) and methyl formate MF (HCOOCH3), and (ii) ethanol EtOH (CH3CH2OH) and dimethyl ether DME (CH3OCH3), onto crystalline water ice surfaces at low temperatures. Both approaches show that, for each pair, the most stable isomer from a thermodynamical point of view, i.e. AA and EtOH, is also the one which is the more tightly bound to the water ice surface compared to the less stable isomers (MF and DME). This finding, which can be explained by the ability of AA or EtOH to efficiently interact with the ice surface via hydrogen bondings, may have important consequences in an astrophysical context, since it could explain why the most stable isomer is not the most abundant observed in the interstellar gas phase. [ABSTRACT FROM AUTHOR]

Published
2013
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