Astrochemistry Programme April 12, 2010 Writing Group Petra Rudolf RUG Groningen Wim Ubachs VU Amsterdam Wybren Jan Buma UvA Amsterdam Ewine van Dishoeck UL Leiden Gerrit Groenenboom RU Nijmegen F. Matthias Bickelhaupt VU Amsterdam Harold Linnartz UL Leiden Xander Tielens UL Leiden Jos Oomens FOM Rijnhuizen, Nieuwegein Pascale Ehrenfreund UL Leiden Ben Feringa RUG Groningen 2 Content 1. General Introduction ________________________________________________ 5 2. Network Goals and Objectives _________________________________________ 7 3. Gas phase astrochemistry ____________________________________________ 9 3.1 Background_________________________________________________________ 9 3.2 Objectives_________________________________________________________ 10 3.3 Projects___________________________________________________________ 12 3.3.1 Photodissociation _______________________________________________ 12 Project 3.1: Photodissociation experiments on small molecules_________________ 13 Project 3.2: Photodissociation and excitation of molecules in protoplanetary disks__ 15 Project 3.3: Photodissociation branching ratios of large molecules ______________ 17 3.3.2. Inelastic collisions ______________________________________________ 19 Project 3.4: Vibration-rotation inelastic collisions____________________________ 20 Project 3.5: Experimental studies of vibration-rotation inelastic collisions_________ 22 Project 3.6: Pure rotational inelastic collisions ______________________________ 23 3.4 Overview of the projects______________________________________________ 24 4. The solid Universe - Dust and Ice - ____________________________________ 29 4.1 Background________________________________________________________ 29 4.2 Objectives_________________________________________________________ 29 4.3 Projects___________________________________________________________ 31 4.3.1. Dust _________________________________________________________ 31 Project 4.1: The physics and chemistry of metallic Fe and FeS nano clusters ______ 32 Project 4.2: Mapping the silicate content in the interstellar dust in the X-rays _____ 34 Project 4.3: Dust surface chemistry in the inner Solar Nebula: The formation of organic molecules through catalytic reactios on silicate surfaces_________________ 36 Project 4.4: A colloidal model system for dust grains in space__________________ 38 4.3.2 Ice __________________________________________________________ 40 Project 4.5: Shining light on molecules ___________________________________ 41 Project 4.6: Molecular complexity in the solid state: theory meets experiment_____ 43 Project 4.7: MD/MC simulations of photo-induced reactions of H2O photofragments with CO ice __________________________________________________________ 46 4.4 Overview of the projects______________________________________________ 48 5. From PAHs to chains, rings and cages __________________________________ 49 5.1 Background________________________________________________________ 49 5.2 Objectives_________________________________________________________ 51 5.3 Projects___________________________________________________________ 53 Project 5.1: The photochemical evolution of PAHs ___________________________ 53 Project 5.2: The chemical evolution of PAHs driven by energetic ion interaction____ 55 Project 5.3: The visible and UV absorption characteristics of stable intermediates __ 57 Project 5.4: Astronomical implications ____________________________________ 59 5.4 Overview of the projects______________________________________________ 61 5.5 PAH samples_______________________________________________________ 61 6. The prebiotic Universe ______________________________________________ 64 6.1 Background________________________________________________________ 64 6.2 Objectives_________________________________________________________ 65 3 6.3 Projects___________________________________________________________ 67 Project 6.1: The building blocks of life in interstellar ice - a combined astrophysical and biochemical laboratory study ____________________________________________ 67 Project 6.2: Formation of Protocells formed from PAHs and fatty acids ___________ 69 Project 6.3: Amino-acid Formation Controlled by Chiral Template _______________ 72 Project 6.4: Formation of Chiral Meteoritic Prebiotic Molecules _________________ 75 6.4 Overview of the projects______________________________________________ 78 7. The Dutch Astrochemistry Network ____________________________________ 79 7.1 Appointments ______________________________________________________ 79 7.2 Network organization ________________________________________________ 79 7.3 Network activities ___________________________________________________ 80 7.4 Budget ___________________________________________________________ 81 8. Expertise of the network ____________________________________________ 82 8.1 Short CV of key personnel ____________________________________________ 83 4 1. General Introduction The origin and evolution of the molecular universe starts with the injection of material – much of it in molecular form – by stars in the later stages of their life, the subsequent processing of this material in the interstellar medium by the prevalent ultraviolet radiation fields, energetic particles, and strong shocks, and ends with the incorporation of this material into newly formed stars and their budding planetary systems (Fig. 1.1). During this evolution, simple molecules and atoms combine to form larger species while complex molecules and dust are broken down to smaller species. This “chemical dance” of the elements leads to a rich and varied chemical inventory in the interstellar medium of galaxies. In the end, the chemical processes taking place in the interstellar medium will be inherited by newly forming planetary systems. Figure 1.1. A schematic of the lifecycle of molecules in the interstellar medium. The chemical processes taking place at every stage in this process – from the birth of molecules in circumstellar shells, their passing through the physical gauntlet of the interstellar medium ultimately fueling star and planet formation – make up the heritage of planetary systems. During this evolution, molecules exert a direct influence on their environment. Molecules dominate the cooling of gas inside dense molecular clouds. Molecules also control the ionization balance in such environments and thereby the coupling of magnetic fields to the gas. Through this influence on the forces supporting clouds against gravity, molecules will affect the process of star formation. Large molecules are also thought to be a major contributor to the heating of diffuse atomic gas in the interstellar medium. Thereby they affect the physical conditions in such environments and the phase structure of the interstellar medium, which set the stage for the star formation process. Likewise, the presence of small molecules may have controlled cooling in the early Universe and in that way the formation of the first stars. Besides through their influence on the processes involved in star formation, molecules provide also key probes of the Universe. Molecules posses a myriad of electronic, vibrational, and rotational levels whose excitation is sensitive to the local physical conditions over a wide range of astrophysically relevant densities and temperatures. Molecular abundances are also sensitive to the local physical conditions. Hence, molecules provide a sensitive probe of the dynamics and the physical and chemical conditions in a wide range of objects at scales ranging from budding planetary systems to galactic and extragalactic sizes. 5 Molecules are directly interwoven into the fabric of the universe. They are an important component of the Universe and play a central role in many key processes that dominate the structure and evolution of galaxies. Understanding the origin and evolution of interstellar and circumstellar molecules is therefore a fundamental goal of modern astrophysics. Likewise, developing molecules as an astronomical tool to study the physical conditions and dynamics of a wide variety of objects in the Universe will be of key importance for astronomy in the coming decade. 6 2. Network Goals and Objectives Over the next five years, European ground-based and space-based missions will open up the Universe to high spatial and spectral resolution studies at infrared and submillimeter wavelengths and astronomical groups in the Netherlands are deeply involved in these efforts. In May 2009, the European Space Agency has launched the Herschel Space Observatory with the heterodyne instrument, HIFI, – developed by an international consortium under PI-ship of the Dutch space agency, SRON – that will open up the THz frequency regime for systematic studies of the chemical inventory and the role of water in space, in particular in regions of star and planet formation. The European Southern Observatory, ESO, is a major partner in the construction of the sub-millimeter interferometer, ALMA, in Chili. When it starts scientific operations in 2011, this interferometer, with its unprecedented spatial resolution and sensitivity at sub-millimeter wavelengths, will be the forefront instrument for studying the cold molecular gas and dust that constitute the very building blocks of stars, planetary systems, and galaxies. The Netherlands Research School For Astronomy (Nederlandse Onderzoeksschool voor Astronomie, NOVA) is responsible for the design and construction of the band 9 receivers for ALMA. NOVA, is also responsible for the design