|Current Workshop | Overview||Back | Home | Search ||
Grain-Surface Networks and Data for Astrochemistry
Over the past decades a large astronomical community interested in understanding physical and chemical processes driving chemical evolution in space has formed, matured, and grown. Molecules in space are synthesized via a large variety of gas-phase reactions and reactions on dust surfaces, where the surface acts as a catalyst. The surface synthesis is particularly important for formation of complex “pre- biotic” organic molecules that are precursors of more complex biomolecules.
For gas-phase chemistry, the astrochemistry community has reached a broad consensus on how to describe it properly in models and present the required data in databases: however, no such consensus has yet been reached for grain-surface chemistry. The idea of this meeting was to bring together astrochemists and laboratory and theoretical chemists to elaborate on the description of surface processes in modern astrochemical models, networks, and databases.
The meeting was a great success. A well-selected team of ~ 25 experts from all around the world (NL, Germany, USA, Japan, Sweden, France, and UK, amongst others) covering observational, laboratory and theoretical (astro)chemistry met between July 28th and August 1st 2014 in the Loretnz Center (Snellius Building) of Leiden University. The Lorentz Center was an amazing place for the meeting as it provides large, well-illuminated meeting rooms with all the required infrastructure (huge blackboards, a projector, and a common area with hot and cold drinks available throughtout the meeting). The Lorentz Center administration was competent and fast in solving organizational problems, and helped make this meeting a success.
The program of the meeting consisted of the 5 key sessions (“Introduction“, “Diffusion rates“, “Surface reaction rates“, “Adsorption and desorption“, and “Layering of ices“). Each session included a review summarizing the current knowledge on the topic, followed by several more specific, detailed talks. At the end of each day, lengthy 2-3 hours discussions were organized, which usually sparked intense debates and brainstorming. This allowed us to identify the key problems to be solved, along with possible approaches to their solutions.
From the SOC point of view, all goals of the meeting were achieved. In summary, participants expressed the need for a standardized database containing grain-surface reactions along with the appropriate data including binding energies, activation barriers, and diffusion barriers. The most important input parameters for astrochemical models were identified, and a roadmap to quantify these parameters was drawn. The laboratory experiments necessary to derive and constrain yet unknown details of surface reactions were proposed. The final output of the longer-term project will be a public and user-friendly database, available through the same websites as the databases for gas-phase reactions (e.g., KIDA). This new public database will be unique in providing coherent data for modeling and interpreting molecular evolution observed in various astrophysical environments, and will likely become heavily used and cited in the ALMA/NOEMA era.
The achieved consensus on a recommended description of surface chemistry in astrochemical models, a standardized description of the chemistry parameters and input format, along with missing data and pending problems, will be presented to the broader astronomical community in a separate scientific paper we intend to submit to a peer-reviewed journal.