Periodic Reporting for period 2 - QUANTUMGRAIN (Quantum Chemistry on Interstellar Grains)
Okres sprawozdawczy: 2022-03-01 do 2023-08-31
We live in a molecular Universe, where we can find from the simplest molecule, H2, up to complex compounds of biological relevance like amino acids. The different steps leading to the formation of a planetary system like the solar one (i.e. from the formation of the star to the formation of the planets) is associated with a chemical evolution, in which at each step more complex molecules are formed. This chemical evolution is fundamental to know our astrochemical roots because it is ultimately connected with the origin of life.
The matter of space is mostly in the gas phase but the chemistry of space cannot be explained only by reactions taking place in the state. Besides, interstellar grains, minute solid particles ubiquitously present in several cosmic environments, play a key role as they provide the surfaces where chemical reactions occur more efficiently.
Traditionally, the interstellar grain chemistry has been investigated by astronomical observations, complemented by numerical models and laboratory experiments. However, this interdisciplinary approach presents some limitations, converging in a lack of atomic-scale information, which is fundamental to fully understand the chemistry occurring on the surfaces of interstellar grains. Because of that, the interstellar grain chemistry is a controversial issue that has baffled astrochemists for decades and its possibly crucial role in the existing chemical diversity and complexity is not well known. Fundamental questions such as “what are the reactions requiring the presence of grains and why?” and “what is the actual role of the grains ion these reactions?” are still unanswered.
The QUANTUMGRAIN (Quantum Chemistry on Interstellar Grains) project has the ambitious ultimate goal to unveil the grain surface chemistry by providing this missing atomic-scale information. This is obtained by state-of-the-art simulations based on quantum mechanical computations. The simulations will provide unique molecular pictures of the different elementary steps involved in the interstellar surface reactions as well unprecedented, quantitative data, essential to disclose the interstellar grain surface chemistry.
To fulfil this overall objective, the project is organized in three Work Packages (WPs), whose specific objectives are:
1) Characterise the detailed atomistic structures of different interstellar grains
2) Explore and characterise at a molecular level different on-grain surface reactions believed to occur during the Solar-type systems birth
3) Assess the actual role played by the grains in these reactions
The matter of space is mostly in the gas phase but the chemistry of space cannot be explained only by reactions taking place in the state. Besides, interstellar grains, minute solid particles ubiquitously present in several cosmic environments, play a key role as they provide the surfaces where chemical reactions occur more efficiently.
Traditionally, the interstellar grain chemistry has been investigated by astronomical observations, complemented by numerical models and laboratory experiments. However, this interdisciplinary approach presents some limitations, converging in a lack of atomic-scale information, which is fundamental to fully understand the chemistry occurring on the surfaces of interstellar grains. Because of that, the interstellar grain chemistry is a controversial issue that has baffled astrochemists for decades and its possibly crucial role in the existing chemical diversity and complexity is not well known. Fundamental questions such as “what are the reactions requiring the presence of grains and why?” and “what is the actual role of the grains ion these reactions?” are still unanswered.
The QUANTUMGRAIN (Quantum Chemistry on Interstellar Grains) project has the ambitious ultimate goal to unveil the grain surface chemistry by providing this missing atomic-scale information. This is obtained by state-of-the-art simulations based on quantum mechanical computations. The simulations will provide unique molecular pictures of the different elementary steps involved in the interstellar surface reactions as well unprecedented, quantitative data, essential to disclose the interstellar grain surface chemistry.
To fulfil this overall objective, the project is organized in three Work Packages (WPs), whose specific objectives are:
1) Characterise the detailed atomistic structures of different interstellar grains
2) Explore and characterise at a molecular level different on-grain surface reactions believed to occur during the Solar-type systems birth
3) Assess the actual role played by the grains in these reactions
The project develops by the participation of seven PhD students and four postdocs (recruited at different stages of the project). In the following, the main work done is summarized.
We modelled and characterized computationally different realistic surfaces of interstellar interest. That is, those constituting the ice mantles, like compact water ice and water mixed with CO, and pure water ice with a porous structure. We have also modelled refractory materials present in interstellar grains and in in comets and meteorites, like silicates, silica, and iron sulphides. In this later case, dedicated electronic microscopy and nanoindentation measurements have been performed on meteoritic samples to determine their structure, composition, and mechanical properties.
The adsorption of a wide set of astrochemically-relevant molecules (O-, N- and S-containing compounds, and interstellar complex organic molecules, iCOMs) interacting with water ice surfaces and silicates have been simulated. With them, unprecedented accurate binding energies have been obtained, which are crucial values to use in numerical models aimed to rationalize the observations.
Different chemical reactions have been simulated on different interstellar surfaces: i) formation of simple interstellar species (e.g. H2O, NH3, CH3OH), formation of organic compounds (e.g. iCOMs, hydrocarbons and alcohols), and formation of biomolecules (e.g. sugars and adenine precursors).
Simulations have also served to determine the capability of interstellar water ices to act as third bodies, in which they absorb the energy released by the reactions, hence stabilizing the formed products. This has been the case for the formation of NH3 iCOMs, where moreover, the energy dissipation mechanism was deciphered.
Results have done deeper insights on the role played by the grains on each of these reactions. We have detected that for some cases the surfaces accelerate the reactions (they act as chemical catalysts). In others, they retain the reactants on the surfaces allowing their encountering. In others they are directly the reactant suppliers (e.g. a component of the ice is a reactant itself). While in others, the surfaces act as third bodies, allowing the occurrence of coupling reactions.
Results are being published in scientific articles in top-ranked journals and presented in diverse international congresses, either in the form of oral presentations or posters. Research group activities have been disseminated in our website (https://www.quantumgrain.eu) and twitter account (@QuantumGrain), where we also disseminate our outreach activities, (e.g. popular science articles, blog posts and podcasts, https://www.quantumgrain.eu/outreach).
We modelled and characterized computationally different realistic surfaces of interstellar interest. That is, those constituting the ice mantles, like compact water ice and water mixed with CO, and pure water ice with a porous structure. We have also modelled refractory materials present in interstellar grains and in in comets and meteorites, like silicates, silica, and iron sulphides. In this later case, dedicated electronic microscopy and nanoindentation measurements have been performed on meteoritic samples to determine their structure, composition, and mechanical properties.
The adsorption of a wide set of astrochemically-relevant molecules (O-, N- and S-containing compounds, and interstellar complex organic molecules, iCOMs) interacting with water ice surfaces and silicates have been simulated. With them, unprecedented accurate binding energies have been obtained, which are crucial values to use in numerical models aimed to rationalize the observations.
Different chemical reactions have been simulated on different interstellar surfaces: i) formation of simple interstellar species (e.g. H2O, NH3, CH3OH), formation of organic compounds (e.g. iCOMs, hydrocarbons and alcohols), and formation of biomolecules (e.g. sugars and adenine precursors).
Simulations have also served to determine the capability of interstellar water ices to act as third bodies, in which they absorb the energy released by the reactions, hence stabilizing the formed products. This has been the case for the formation of NH3 iCOMs, where moreover, the energy dissipation mechanism was deciphered.
Results have done deeper insights on the role played by the grains on each of these reactions. We have detected that for some cases the surfaces accelerate the reactions (they act as chemical catalysts). In others, they retain the reactants on the surfaces allowing their encountering. In others they are directly the reactant suppliers (e.g. a component of the ice is a reactant itself). While in others, the surfaces act as third bodies, allowing the occurrence of coupling reactions.
Results are being published in scientific articles in top-ranked journals and presented in diverse international congresses, either in the form of oral presentations or posters. Research group activities have been disseminated in our website (https://www.quantumgrain.eu) and twitter account (@QuantumGrain), where we also disseminate our outreach activities, (e.g. popular science articles, blog posts and podcasts, https://www.quantumgrain.eu/outreach).
QUANTUMGRAIN is a quantum chemistry-based project, in which computational simulations is the main mean to fulfil its main objective (and solve a major problem in Astrochemistry): to unveil interstellar grains in the chemical enrichment of a nascent Solar-type planetary system. The project consists of non-oriented fundamental research. Thus, its main aim is to further advance knowledge to make it available to society. Here, the new knowledge will rely on Astrocatalysis as an enhancer on the formation of interstellar compounds, thereby improving models explaining, ultimately, our astrochemical origins.
By reaching this target, we will also be capable to solve other related important issues:
i) to know the actual role of the interstellar grains in relevant surface reactions contributing to the molecular content present in space
ii) to have complete, unique molecular descriptions (i.e. the missing atomic-scale information) of the studied processes, which will be very used as accurate input parameters in the numerical models
iii) to determine the contribution of the interstellar grain chemistry in the overall chemistry of the Universe, hence helping to solve the challenging “cosmic chemical evolution” jigsaw puzzle.
The project will also contribute to the excellence, dynamism, and creativity, strengthening the European scientific research by providing excellent science and boosting quantum chemistry applied to space science. Space science represents an important inspirational tool for exciting and motivating young people and encouraging them to choose scientific careers. Space is also a domain that easily captures the interest of students towards education paths in the fields of science and technology. Huge investments are currently dedicated to observational ground/space borne instruments, also in Europe. It is a well-known fact that human activity linked to space exploration, detection of cosmic prebiotic molecules, search for propitious conditions for the emergence of life in exoplanets, etc., are all milestones in our attempt to clarify how life has emerged and how widespread is in the Universe.
By reaching this target, we will also be capable to solve other related important issues:
i) to know the actual role of the interstellar grains in relevant surface reactions contributing to the molecular content present in space
ii) to have complete, unique molecular descriptions (i.e. the missing atomic-scale information) of the studied processes, which will be very used as accurate input parameters in the numerical models
iii) to determine the contribution of the interstellar grain chemistry in the overall chemistry of the Universe, hence helping to solve the challenging “cosmic chemical evolution” jigsaw puzzle.
The project will also contribute to the excellence, dynamism, and creativity, strengthening the European scientific research by providing excellent science and boosting quantum chemistry applied to space science. Space science represents an important inspirational tool for exciting and motivating young people and encouraging them to choose scientific careers. Space is also a domain that easily captures the interest of students towards education paths in the fields of science and technology. Huge investments are currently dedicated to observational ground/space borne instruments, also in Europe. It is a well-known fact that human activity linked to space exploration, detection of cosmic prebiotic molecules, search for propitious conditions for the emergence of life in exoplanets, etc., are all milestones in our attempt to clarify how life has emerged and how widespread is in the Universe.