Danna Qasim

Danna Qasim
Southwest Research Institute · Space Science and Engineering Division

Doctor of Philosophy

About

36
Publications
2,935
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479
Citations
Citations since 2016
36 Research Items
479 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150

Publications

Publications (36)
Article
Full-text available
A number of recent experimental studies have shown that solid-state complex organic molecules (COMs) can form under conditions that are relevant to the CO freeze-out stage in dense clouds. In this work, we show that alcohols can be formed well before the CO freeze-out stage (i.e., during the very early stage of the H2O-rich ice phase). This joint e...
Article
Full-text available
Methane is one of the simplest stable molecules that is both abundant and widely distributed across space. Observational surveys of CH4 ice towards low- and high-mass young stellar objects showed that much of the CH4 is expected to be formed by the hydrogenation of C on dust grains, and that CH4 ice is strongly correlated with solid H2O. However, t...
Article
Full-text available
The design, implementation, and performance of a customized carbon atom beam source for the purpose of investigating solid-state reaction routes in interstellar ices in molecular clouds are discussed. The source is integrated into an existing ultrahigh vacuum setup, SURFace REaction SImulation DEvice (SURFRESIDE²), which extends this double atom (H...
Article
Full-text available
Uracil is one of the four RNA nucleobases and a component of meteoritic organics. If delivered to the early Earth, uracil could have been involved in the origins of the first RNA-based life, and so this molecule could be a biomarker on other worlds. Therefore, it is important to understand uracil's survival to ionizing radiation in extraterrestrial...
Article
Full-text available
Gas-phase and solid-state chemistry in low-temperature interstellar clouds and cores leads to a D/H enhancement in interstellar ices, which is eventually inherited by comets, meteorites, and even planetary satellites. Hence, the D/ H ratio has been widely used as a tracer for the origins of extraterrestrial chemistry. However, the D/H ratio can als...
Preprint
Full-text available
Gas-phase and solid-state chemistry in low-temperature interstellar clouds and cores leads to a D/H enhancement in interstellar ices, which is eventually inherited by comets, meteorites, and even planetary satellites. Hence, the D/ H ratio has been widely used as a tracer for the origins of extraterrestrial chemistry. However, the D/H ratio can als...
Article
Full-text available
Methane is typically thought to be formed in the solid state on top of cold interstellar icy grain mantles via the successive atomic hydrogenation of a carbon atom. In the current work we investigate the role of molecular hydrogen in the CH 4 reaction network. We make use of an ultrahigh vacuum cryogenic setup combining an atomic carbon atom beam w...
Article
Full-text available
Simple and complex organic molecules (COMs) are observed along different phases of star and planet formation and have been successfully identified in prestellar environments such as dark and translucent clouds. Yet the picture of organic molecule formation at those earliest stages of star formation is not complete and an important reason is the lac...
Article
Full-text available
Context. Methoxymethanol (CH 3 OCH 2 OH) has been identified through gas-phase signatures in both high- and low-mass star-forming regions. Like several other C-, O-, and H-containing complex organic molecules (COMs), this molecule is expected to form upon hydrogen addition and abstraction reactions in CO-rich ice through radical recombination of CO...
Preprint
Full-text available
Methoxymethanol (CH3OCH2OH, MM) has been identified through gas-phase signatures in both high- and low-mass star-forming regions. This molecule is expected to form upon hydrogen addition and abstraction reactions in CO-rich ice through radical recombination of CO hydrogenation products. The goal of this work is to investigate experimentally and the...
Preprint
Full-text available
Simple and complex organic molecules (COMs) are observed along different phases of star and planet formation and have been successfully identified in prestellar environments such as dark and translucent clouds. Yet the picture of organic molecule formation at those earliest stages of star formation is not complete and an important reason is the lac...
Preprint
Full-text available
We report new computational and experimental evidence of an efficient and astrochemically relevant formation route to formaldehyde (H 2 CO). This simplest carbonylic compound is central to the formation of complex organics in cold in-terstellar clouds, and is generally regarded to be formed by the hydrogenation of solid-state carbon monoxide. We de...
Preprint
We report new computational and experimental evidence of an efficient and astrochemically relevant formation route to formaldehyde (H$_2$CO). This simplest carbonylic compound is central to the formation of complex organics in cold interstellar clouds, and is generally regarded to be formed by the hydrogenation of solid-state carbon monoxide. We de...
Preprint
Methane is typically thought to be formed in the solid state on the surface of cold interstellar icy grain mantles via the successive atomic hydrogenation of a carbon atom. In the current work we investigate the potential role of molecular hydrogen in the CH$_4$ reaction network. We make use of an ultra-high vacuum cryogenic setup combining an atom...
Article
Full-text available
The detection of the amino acid glycine and its amine precursor methylamine on the comet 67P/Churyumov-Gerasimenko by the Rosetta mission provides strong evidence for a cosmic origin of amino acids on Earth. How and when such molecules form along the process of star formation remains debated. Here we report the laboratory detection of glycine forme...
Preprint
Full-text available
The detection of the amino acid glycine and its amine precursor methylamine on the comet 67P/Churyumov-Gerasimenko by the Rosetta mission provides strong evidence for a cosmic origin of prebiotics on Earth. How and when such complex organic molecules form along the process of star- and planet-formation remains debated. We report the first laborator...
Preprint
Full-text available
The design, implementation, and performance of a customized carbon atom beam source for the purpose of investigating solid-state reaction routes in interstellar ices in molecular clouds are discussed. The source is integrated into an existing ultrahigh vacuum setup, SURFace REaction SImulation DEvice (SURFRESIDE$^{2}$), which extends this double at...
Preprint
Methane is one of the simplest stable molecules that is both abundant and widely distributed across space. It is thought to have partial origin from interstellar molecular clouds, which are near the beginning of the star formation cycle. Observational surveys of CH$_4$ ice towards low- and high-mass young stellar objects showed that much of the CH$...
Article
Full-text available
Context. Complex organic molecules (COMs) have been identified toward high- and low-mass protostars as well as molecular clouds, suggesting that these interstellar species originate from the early stage(s) of starformation. The reaction pathways resulting in COMs described by the formula C 2 H n O, such as acetaldehyde (CH 3 CHO), vinyl alcohol (CH...
Preprint
Full-text available
Complex organic molecules (COMs) have been identified toward high- and low-mass protostars as well as molecular clouds, suggesting that these interstellar species originate from the early stage(s) of starformation. The reaction pathways resulting in COMs described by the formula C$_2$H$_\text{n}$O are still under debate. In this work, we investigat...
Preprint
Full-text available
Complex organic molecules (COMs) have been detected in the gas-phase in cold and lightless molecular cores. Recent solid-state laboratory experiments have provided strong evidence that COMs can be formed on icy grains through 'non-energetic' processes. In this contribution, we show that propanal and 1-propanol can be formed in this way at the low t...
Article
Full-text available
Context. 1-propanol (CH 3 CH 2 CH 2 OH) is a three carbon-bearing representative of the primary linear alcohols that may have its origin in the cold dark cores in interstellar space. To test this, we investigated in the laboratory whether 1-propanol ice can be formed along pathways possibly relevant to the prestellar core phase. Aims. We aim to sho...
Article
Full-text available
Context. Formic acid (HCOOH) and carbon dioxide (CO 2 ) are simple species that have been detected in the interstellar medium. The solid-state formation pathways of these species under experimental conditions relevant to prestellar cores are primarily based off of weak infrared transitions of the HOCO complex and usually pertain to the H 2 O-rich i...
Preprint
1-propanol (CH3CH2CH2OH) is a three carbon-bearing representative of primary linear alcohols that may have its origin in the cold dark cores in interstellar space. To test this, we investigated in the laboratory whether 1-propanol ice can be formed along pathways possibly relevant to the prestellar core phase. We aim to show in a two-step approach...
Preprint
Formic acid (HCOOH) and carbon dioxide (CO2) are simple species that have been detected in the interstellar medium. The solid-state formation pathways of these species under experimental conditions relevant to prestellar cores are primarily based off of weak infrared transitions of the HOCO complex and usually pertain to the H2O-rich ice phase, and...
Preprint
Full-text available
A number of recent experimental studies have shown that solid-state complex organic molecules (COMs) can form under conditions that are relevant to the CO freeze-out stage in dense clouds. In this work, we show that alcohols can be formed well before the CO freeze-out stage (i.e., in the H2O-rich ice phase). This joint experimental and computationa...
Article
The role of H 2 in forming interstellar complex organics is still not clear due to the high activation energies required for “non-energetic” association reactions. In this work, we investigated the potential contribution of H 2 to the hydrogenated species (H n NCO) formation on dust grains when the “energetic” processing is involved. The goal is to...
Article
Complex organic molecules (COMs) have been detected in the gas-phase in cold and lightless molecular cores. Recent solid-state laboratory experiments have provided strong evidence that COMs can be formed on icy grains through ‘non-energetic’ processes. In this contribution, we show that propanal and 1-propanol can be formed in this way at the low t...
Article
Full-text available
Context. In dense clouds, hydrogenation reactions on icy dust grains are key in the formation of molecules, like formaldehyde, methanol, and complex organic molecules (COMs). These species form through the sequential hydrogenation of CO ice. Although molecular hydrogen (H 2 ) abundances can be four orders of magnitude higher than those of free H-at...
Article
Full-text available
Context. The formation of methanol (CH 3 OH) on icy grain mantles during the star formation cycle is mainly associated with the CO freeze-out stage. Yet there are reasons to believe that CH 3 OH also can form at an earlier period of interstellar ice evolution in CO-poor and H 2 O-rich ices. Aims. This work focuses on CH 3 OH formation in a H 2 O-ri...
Article
Full-text available
The astronomical gas-phase detection of simple species and small organic molecules in cold pre-stellar cores, with abundances as high as ∼10⁻⁸-10⁻⁹ n H, contradicts the generally accepted idea that at 10 K, such species should be fully frozen out on grain surfaces. A physical or chemical mechanism that results in a net transfer from solid-state spe...
Article
The surface of an analogue to the meteoritic mineral schreibersite or (Fe,Ni)3P was investigated to provide insight into the interaction of the mineral surface with prebiotic molecules such as water, methanol, and formic acid. A protocol for creating synthetic metal-phosphide samples with a surface reflectivity suitable for reflection–absorption in...
Article
Full-text available
Observational studies reveal that complex organic molecules (COMs) can be found in various objects associated with different star formation stages. The identification of COMs in prestellar cores, i.e., cold environments in which thermally induced chemistry can be excluded and radiolysis is limited by cosmic rays and cosmic ray induced UV-photons, i...
Article
Full-text available
Complex organic molecules (COMs) have been identified in different environments in star-forming regions. Laboratory studies show that COMs form in the solid state, on icy grains, typically following a ‘non-energetic’ (atom-addition) or ‘energetic’ (UV photon absorption) trigger. So far, such studies have been largely performed for single processes....
Article
We present a study of the reactions of the meteoritic mineral schreibersite (Fe,Ni)3P, focusing primarily on surface chemistry and prebiotic phosphorylation. In this work, a synthetic analogue of the mineral was synthesized by mixing stoichiometric proportions of elemental iron, nickel and phosphorus and heating in a tube furnace at 820°C for appro...
Article
The study of the surface of a meteoritic mineral, schreibersite (Fe,Ni)3P, was investigated to provide insight into the role of the mineral’s surface in aqueous-phase phosphorylation reactions. The optimization of a custom-designed ultrahigh vacuum (UHV) apparatus and Fe2NiP (schreibersite) surface was performed to permit surface science analysis....

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