A5071967164- Astro and Planetary Science
- Mass Spectrometry Techniques and Applications
- Origins and Evolution of Life
- Advanced Chemical Physics Studies
- Photoreceptor and optogenetics research
- Astrophysics and Star Formation Studies
- Planetary Science and Exploration
- Nuclear Physics and Applications
- Isotope Analysis in Ecology
- Atomic and Molecular Physics
- Atmospheric Ozone and Climate
- Photosynthetic Processes and Mechanisms
- Molecular spectroscopy and chirality
- Atmospheric chemistry and aerosols
- Stellar, planetary, and galactic studies
- Enzyme Structure and Function
- Spectroscopy and Quantum Chemical Studies
- Catalytic Processes in Materials Science
- Methane Hydrates and Related Phenomena
- Electrochemical Analysis and Applications
- Geology and Paleoclimatology Research
- Scientific Research and Discoveries
- Molecular Spectroscopy and Structure
- Electron and X-Ray Spectroscopy Techniques
- Light effects on plants
University of Bremen
2014-2023
Institut für Technische und Angewandte Physik (Germany)
2021
Institut d'Astrophysique Spatiale
2004
Centre National de la Recherche Scientifique
2004
Comets harbor the most pristine material in our solar system form of ice, dust, silicates, and refractory organic with some interstellar heritage. The evolved gas analyzer Cometary Sampling Composition (COSAC) experiment aboard Rosetta’s Philae lander was designed for situ analysis molecules on comet 67P/Churyumov-Gerasimenko. Twenty-five minutes after Philae’s initial touchdown, COSAC mass spectrometer took a spectrum sniffing mode, which displayed suite 16 compounds, including many...
Amino acids identified in the Murchison chondritic meteorite by molecular and isotopic analysis are thought to have been delivered early Earth asteroids, comets, interplanetary dust particles where they may triggered appearance of life assisting synthesis proteins via prebiotic polycondensation reactions [Oró, J. (1961) Nature 190, 389–390; Chyba, C. F. & Sagan, (1992) 355, 125–132]. We report identification diamino new enantioselective GC-MS analyses. dl -2,3-diaminopropanoic acid,...
One hand clapping: Based on solid-state circular dichroism data, the leucine (π*, π1)-electronic transition is excited with right circularly polarized synchrotron radiation (r-CPSR) at 182 nm (see scheme). This treatment induced an enantiomeric excess of 2.6 % D-leucine. The results support assumption that interstellar asymmetric photoreactions are capable inducing significant enrichments in amino acids. Supporting information for this article available WWW under...
More than 50 stable organic molecules have been detected in the interstellar medium (ISM), from ground-based and onboard-satellite astronomical observations, gas solid phases. Some of these organics may be prebiotic compounds that were delivered to early Earth by comets meteorites triggered first chemical reactions involved origin life. Ultraviolet irradiation ices simulating photoprocesses cold matter astrophysical environments shown photochemistry can lead formation amino acids related...
Extending CD spectroscopy: Strong circular dichroic (CD) transitions in amino acids were observed when spectroscopy was extended to the vacuum-ultraviolet spectral range between 140 and 190 nm (see picture). Here, proteinogenic show same magnitude sign, circularly polarized light is thus capable of inducing enantiomeric excesses handedness. Interestingly, typical "meteoritic" have different properties. Biopolymers such as nucleic proteins are composed chiral monomers that identical...
Light on chirality: To predict the enantiomeric enrichment that can be induced into racemic organic molecules with help of circularly polarized light, anisotropy factor g is essential. Anisotropy spectra g=f(λ) recorded for proteinaceous amino acids provide crucial information transfer chirality from light to matter. Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available...
Aims.Two irradiation experiments on interstellar ice analogs at 80 K under interstellar-like conditions were performed with the LURE SU5 synchrotron beamline to assess, for first time, photochemical effect of circularly polarized ultraviolet light (UV CPL) 167 nm (7.45 eV) right and left polarizations such mixtures.
Abstract Amino acids that pass the RNA machinery in living organisms occur L ‐configuration. The question on evolutionary origin of this biomolecular asymmetry remains unanswered to day. were detected artificially produced interstellar ices, and ‐enantiomer‐enriched amino identified CM‐type meteorites. This hints at a possible interstellar/circumstellar themselves as well their stereochemical asymmetry. Based upon current knowledge about occurrence circularly‐polarized electromagnetic...
The formation of the prebiotically relevant molecule formamide under electron exposure ammonia and carbon monoxide was studied at cryogenic temperatures 30–35 K. Postirradiation thermal desorption spectroscopy used to study energy dependence reaction. A resonant process centered around ∼9 eV a threshold type increase yield above ∼12 were observed. On basis absence particular side products such as urea ethanediamide supported by quantum chemical calculations, reaction mechanisms related two...
ABSTRACT The basic units that constitute essential biopolymers (proteins and nucleic acids) are enantiomerically biased. Proteins constructed from L‐amino acids possess a backbone composed exclusively of D‐sugars. Photochirogenesis has been postulated to be the source this homochirality biomolecules: Asymmetric photochemical reactions were catalyzed by circularly polarized light (cpl) in interstellar environments generated first chiral prebiotic precursors. Enantiomers absorb cpl differently...
Current research focuses on a better understanding of the origin biomolecular asymmetry by identification and detection possibly first chiral molecules that were involved in appearance evolution life Earth. We have reasons to assume these specific amino acids. Chiral acids been identified both chondritic meteorites simulated interstellar ices. Present circularly polarized electromagnetic radiation was environments an asymmetric photon-molecule interaction might triggered symmetry breaking....
Self-assembled monolayers (SAMs) of 10-undecene-1-thiol on Au were functionalized with nitrogen-containing groups using an approach in which multilayer ammonia (NH3) films deposited at low temperature onto the SAMs and subsequently exposed to 15 eV electrons. The result this process was investigated after removal remaining NH3 by annealing room high-resolution electron energy loss spectroscopy (HREELS) X-ray photoelectron (XPS). HREELS shows that CC double bonds disappear during exposure,...
Thermal desorption spectrometry (TDS) was applied to investigate reactions initiated by electron exposure of multilayer condensed films containing both an olefin and amine or ammonia. In all cases, electron-induced hydroamination leading addition ammonia the C═C double bond were detected. The dependence product yield on energy studied for mixtures ethene with ammonia, ethylamine, diethylamine points, in three ionization-driven process. Concurrent include formation larger hydrocarbons as well...
The processing of cryogenic ices consisting water and carbon monoxide by different types radiation is known to lead the formation dioxide, formic acid, formaldehyde, also methanol. In this study, we have investigated these reactions upon electron irradiation with energies between 2 20 eV, an energy range typically found in secondary electrons. This first time that been monitored a sufficiently fine step width resolve identify primary electron–molecule interactions leading specific products....
The most pristine material of the Solar System is assumed to be preserved in comets form dust and ice as refractory matter. ESA's mission Rosetta its lander Philae had been developed investigate nucleus comet 67P/Churyumov-Gerasimenko situ. Twenty-five minutes after initial touchdown on surface 67P November 2014, a mass spectrum was recorded by time-of-flight spectrometer COSAC onboard Philae. new characterization this through non-negative least squares fitting Monte Carlo simulations...
Amino acids are involved in many scientific theories elucidating possible origins of life on Earth. One the challenges when discussing evolutionary origin biopolymers such as proteins and oligonucleotides living organisms is phenomenon that these polymers implement monomers exclusively one handedness, a feature called biomolecular homochirality. Many attempts have been made to understand this process racemic symmetry breaking. Assuming an extraterrestrial molecular building blocks organisms,...
Electron-induced reactions in condensed mixtures of ethylene and water lead to the synthesis ethanol, as shown by post-irradiation thermal desorption spectrometry (TDS). Interestingly, this is not only induced soft electron impact ionization similar a previously observed electron-induced hydroamination but also, at low energy, attachment subsequent acid/base reaction with water.
The formation of methane (CH4), formaldehyde (H2CO), ethylene glycol (HOCH2CH2OH), methoxymethanol (CH3OCH2OH), dimethyl ether (CH3OCH3), and ethanol (CH3CH2OH) upon electron irradiation condensed multilayer adsorbates CH3OH as a model cosmic ice has been monitored by the combined use electron-stimulated thermal desorption experiments. energy-dependent relative yields all products were measured between 2.5 20 eV, reaction mechanisms product deduced. energy dependences HOCH2CH2OH, CH3OCH2OH,...
Multilayer condensed films of trimethyl(methylcyclopentadienyl)-platinum(IV) (MeCpPtMe3) have been exposed to low-energy electrons at incident electron energies 15, 30, and 500 eV. The reactions occurring under exposure investigated using high-resolution energy loss (HREEL) spectroscopy. observed changes in the HREEL spectra upon are similar for three different energies. Contrary previous results obtained irradiation eV reflection absorption infrared spectroscopy (RAIRS) pointing toward a...