Challenges in modelling the reaction chemistry of interstellar dust

Organisers: Fedor Goumans (Leiden), Ben Slater (London), Stefan Bromley (Barcelona)

 

The burgeoning and strongly interdisciplinary field of astrochemistry has built upon the enormous recent growth and development in our experimental, observational and theoretical efforts to understand the chemical processes occurring in the interstellar medium. Astrochemical research efforts have increasingly focussed on the role of dust grains as it has become clear that these are of crucial importance for interstellar chemical evolution. The aim of this workshop was to improve the accuracy and scope of modelling reactive processes on realistic interstellar dust grain models, specifically through identifying

1) realistic models for bare and ice-covered interstellar dust grains surfaces

2) ways of adequately dealing with quantum tunnelling and weak interactions

3) extrapolation schemes of accurate rate constants to astrochemical models

4) a concrete list of priority problems that are addressable by new collaborations

 

The workshop covered a broad scope of the scientific theme, through observations and experiments of ices, dust and their chemistry, theoretical calculations of these and finally long-time scale astronomical modelling. Because of this diverse exposure none of the attendees knew all participants before the workshop which has led to cross-fertilisation of ideas across disciplines. Many lively discussions were observed during the informal discussion time after lunch and throughout the social events.

We have asked the Chief Editor of Physical Chemistry Chemical Physics if he would be interested in a, high-profile, perspective article, covering the issues that were discussed in the workshop. He was personally looking forward to such a contribution. To this extent the organisers are currently collaborating with 3 workshop participants to put together this article covering the current state-of-the-art and a roadmap towards achieving the 4 goals stated above. During the course of the workshop it turned out that good progress has been made the last few years towards goal 1), and we have good hope that more and more accurate models will be achieved in the near future through collaborative efforts. It transpired that goal 2) was for a large part already achieved in the very recent past and that further progress can be foreseen with more powerful computers to study larger, more precise systems. The third goal can only be achieved by a closer collaboration and clearer communication across all disciplines so that the measured and calculated rate data can be translated for use in astronomical models – this workshop will contribute significantly towards that. From the discussion session at the end of each day we already have a long-list of priority problems (goal 4), which we will further delineate in the course of writing the perspective article.

 

The format of the workshop was very accommodating towards setting up conversations across disciplines and between people that did know each other before the meeting. Especially the Monday evening social event opened up interactions, helped by a perfect size of the group (~50, we would certainly not recommend a bigger group, 40-50 seems ideal), and attendees coming from very many different institutions, avoiding ‘cliquing’. The lively discussion during coffee and lunch breaks, informal and formal discussion sessions always seemed to involve different combinations of people, and we therefore have to conclude that we have managed to achieve new links between people, which we hope to establish in long-lasting collaborations advancing this interesting, interdisciplinary field.