LASSIE: A Marie Curie Training Network on Astrochemistry u-cergy.fr/LERMA-LAMAP/LASSIE/

1. LASSIE: A Marie Curie Training Network on Astrochemistryhttp://www.u-cergy.fr/LERMA-LAMAP/LASSIE/ Nigel Mason Centre for Earth, Planetary, Astronomy & Space Research The Open University, UK n.j.mason@open.ac.uk

2. Project acronym: LASSIE • Project full title: LABORATORY ASTROCHEMICAL SURFACE SCIENCE IN EUROPE 1 (Coordinator) Heriot-Watt University Prof Martin McCoustra 2 Aarhus University 3 Paris Observatory OBSParis 4 University of Münster 5 Max-Plank-Gessellschaft 6 National Institute for Astrophysics INAF 7 Leiden University 8 Chalmers University Chalmers 9 University of Gothenburg 10 University College London 11 The Open University 12 Queen’s University, Belfast 13 Strathclyde University 14 Graphic Science 15 Gridcore AB Gridcore 16 Hiden Analytical Ltd. 17 Kore Technology Ltd. Chemistry of Planets

3. LASSIE ITN • The LASSIE Initial Training Network is; • A large inclusive network that will allow interactions across the surface and solid state astrochemistry communities in Europe to be developed. • Provides the necessary knowledge base and human resources to ensure that the past, present and future multibillion Euro support for observational astronomy is capable of being fully exploited by providing the necessary scientific support to allow astronomers to interpret their observations based on realistic and well-understood laboratory chemistry and physics. • Provides a much needed infrastructure for developing a coherent programme of astrochemical research within the EU that will allow the ERA to compete more effectively globally. Chemistry of Planets

4. LASSIE Science Programme aims • To understand the formation and destruction of interstellar dust. • To understand the formation of simple molecules, and hence icy mantles, on realistic models of (icy) dust grain surfaces. • To understand the physical processes that result when an icy grain mantle is heated or irradiated with light, electrons or ions. • To understand the chemical processes that result when an icy grain mantle is heated or irradiated with light, electrons or ions. • To understand the role of these processes in observations of grains, ices and the molecules formed by the intermediary of grains and their icy mantles in the evolving Universe. Chemistry of Planets

5. LASSIE 5 THEMES • Theme 1 - Formation of Grains, Small Molecules and Ices Link to Eurogenesis ?? As A Tielens said === star death • The mechanism of formation of interstellar dust grains from their initial condensation through to grain aggregate formation via grain-grain collisions (MPG, OU, UM). • The release of reaction energy into product translation, rotation and vibration in the heterogeneous formation of small molecules on model dust grain surfaces (AU, Chalmers, INAF, OBSParis, UCL,UM). • The rates of molecule and ice formation on dust grain surfaces, including studies of isotopic fractionation (AU, Chalmers, HWU, LUO, INAF, OBSParis, UCL). • The morphology of ices formed reactively on model grain surfaces (AU, Chalmers, HWU, INAF, OBSParis, UCL). • The infrared, optical and ultraviolet (UV) spectroscopy of ices formed reactively on model dust grain surfaces (Chalmers, HWU, LUO, OU, UCL). Chemistry of Planets

6. LASSIE 5 THEMES • Theme 2 - Physical Processes in and on Icy Grains • Understanding the thermal desorption of simple ices, complex mixed ices and clathrates as observed in the cold, dense regions of the ISM associated with star formation (Chalmers, HWU, LUO, OBSParis, • SU, UCL). • Understanding desorption of simples ices, complex mixed ices and clathrates induced through interaction with electromagnetic radiation (Chalmers, HWU, LUO, OU, SU, UM, UCL). • Understanding desorption of simple ices, complex mixed ices and clathrates induced via interaction with low energy electrons and models of cosmic rays (AU, Chalmers, HWU, INAF, OU, QUB). • Understanding the role of heat, electromagnetic radiation and cosmic rays in promoting changes in ice morphology (HWU, LUO, INAF, OBSParis, OU, UCL, SU). Chemistry of Planets

7. LASSIE 5 THEMES • Theme 3 - Chemical Transformations in and on Icy Grains • UV photon-induced chemical transformations (HWU, LUO, OU, UCL). • Low energy electron-induced chemical transformations (AU, HWU, INAF, OU, UCL). • VUV, XUV and X-ray photon- and cosmic ray-induced chemical transformations (AU, HWU, LUO,INAF, OU, UM, QUB • Chemical transformations following atom, radical or thermal molecular ion bombardment (HWU, INAF, LUO, OBSParis,UCL). Chemistry of Planets

8. LASSIE 5 THEMES • Theme 4 - Modelling the Gas-Grain Interaction • Developing models of amorphous ices and dust grains (LUO, OBSParis, QUB, SU, UGOT). • Calculating IR and UV absorption spectra for water and adsorbates on and in crystalline and amorphous ices (HWU, UGOT). • Understanding the dynamics of photon-driven processes in amorphous ices, including photodesorption and photodissociation (HWU, LUO, OBSParis, UGOT). • Understanding molecular hydrogen and small molecule formation on silicates, carbonaceous, graphite and amorphous ice (AU, LUO, OBSParis, UGOT, QUB). • Understanding the hydrogenation and deuteration reactions of CO in various types of ice, particularly CH3OH formation (LUO, OBSParis, UGOT, QUB, SU). • Calculating diffusion and desorption rates of H atoms, O atoms and simple molecules on amorphous and crystalline ices of various compositions (OBSParis, UGOT). • Modelling coupled grain growth and chemistry under interstellar conditions (MPG). • Simulating the growth and evolution of water ice and other solids under interstellar conditions • (LUO). Chemistry of Planets

9. LASSIE 5 THEMES • Theme 5 - Observations and Astronomical Models Involving Dust and Ices • Large and small scale maps of infrared lines of H2 and deuterated species will be constructed to trace H2 formation on grain surfaces under different conditions (AU, OBSParis). • An inventory of ices in different environments will be assembled using infrared spectroscopy from the Spitzer Space Telescope (INAF, LUO, UCL, SU). • Constraints on ice formation will be obtained by ice mapping with the AKARI satellite (UCL, SU). • A line survey of massive- and intermediate- star forming regions with the Submillimeter Array will be conducted in order to search for complex molecules, which may point to formation routes on grain surfaces (MPG, QUB). Chemistry of Planets

10. LASSIE 5 THEMES • Theme 5 - Observations and Astronomical Models Involving Dust and Ices • A determination of the formation and lifecycle of water from gas to solid and back again will be performed by combining infrared spectroscopy of water ice with submillimeter spectroscopy of water gas from the Herschel Space Observatory (LUO, UCL, SU). • A study of the formation and composition of silicate and carbonaceous grains in disks and envelopes around young and old stars will be undertaken using infrared spectroscopy (MPG, UCL). • High spatial resolution IR spectroscopy of PDRs in nebulae and around stars will be recorded, looking at how the emission band strengths and relative intensities vary with distance from the exciting source as a diagnostic of PAH formation and excitation mechanisms (OBSParis, UCL). • Modelling of the gas-grain chemistry in hot cores and disks using the new laboratory data and comparison with observations (UCL, LUO, MPG, OBSParis, QUB, UCL, SU). Chemistry of Planets

11. The Interstellar Medium is rich in molecules… from the simplest molecule (H2) to those necessary for the formation of life Credit: R.Ruiterkamp

12. >160 Interstellar Molecules Glycine ? Acetic Acid Benzene Glycolaldehyde Cyanopolyynes Formic Acid National Radio Astronomy Observatory http://www.cv.nrao.edu/~awootten/allmols.html

13. What chemistry can occur in such environments ? • Temperatures are low … (As low as 10K) • In the ISM the density is extremely low … so probability of collisions is low • Hence it appears impossible to support chemistry ! But evidence shows there must be complex chemistry ! Chemistry of Planets

14. What chemistry can occur in such environments ? • At low temperatures there is little or no thermal/kinetic energy • So chemistry must occur through barrierless • Reactions. • Or • Stimulated reactions ( e.g. photon assisted) Chemistry of Planets

15. What chemistry can occur in such environments ? Ion-Molecule reactions are a typical example of a reaction that may have no activation barrier. e.g. NH3+ + H2 NH4+ + H Ar+ + H2 ArH+ + H He+ + H2 He + H+ + H H2- + H  H + H2 + e- (Note anions as well as cations !) Chemistry of Planets

16. What chemistry can occur in such environments ? However neutral – neutral reactions can also occur at low temperatures. H2O + Cl  HCl + O F + D2  DF + D Indeed the reaction rate may INCREASE as the temperature falls It has been suggested that the increasing rate of these reactions as the temperature is lowered is related to the changing distribution of reagents over their rotational levels as the temperature is lowered. • Hence State Selective experiments are required Chemistry of Planets

17. What chemistry can occur in such environments ? Supersonic crossed beam machine for radical-radical studies. CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme) to study neutral-neutral reactions and energy transfer processes in the gas phase down to temperatures as low as ~10 K. (Rennes)

18. What chemistry can occur in such environments ? But such gas phase experiments can not explain all the chemistry in the ISM E.g. the formation of H2…. the most common molecule in the ISM can not be formed in the gas phase Instead it is formed by reactions on DUST Surfaces ! Chemistry of Planets

19. Chemistry on Dust grains • Some of these grains are covered with an icy mantle formed by freezing out of atoms/molecules from the gas phase • Hence we need to explore ice chemistry ! • The ices in the mantle are bombarded with cosmic rays, Ions, solar UV, electrons. • Chemical modification occurs. Chemistry of Planets

20. Cryogen inlet via transfer line Temperature controller Continuous flow cryostat Ion gauge To pumping station Resistive heater Copper sample mount MgF2/ZnSe substrate Thermocouples Detectors - UV-VIS / FTIR detector - Photomultiplier Tube • Sources • UV-VIS / FTIR spectrometer • Synchrotron Sources E-gun Synchrotron Ion Source 25.2 • HV (UHV) chamber - Portable: • P~10-8 - 10-10 mbar • Still > a million times higher than ISM! • Temperature • Continuous flow LHe/LN2 cryostat • 12 K < T < 450 K • Substrate • CaF2 / MgF2 (VUV) or ZnSe (IR) window • transmission spectroscopy of bulk ices • Samples • deposited in situ by vapour deposition • 0.1 – 1 m • Thick enough to ignore the effects of the substrate • Looking at bulk ice reactions

21. Experiments at Synchrotron FacilitiesUK DaresburyAarhus Denmark

22. Recent results on astrochemical ice morphology (Theme 1) • Study electronic state spectroscopy of molecules in the solid phase (photolysis). • VUV and IR spectroscopy of ice morphology. • Experiments performed in transmission mode.

23. VUV Spectrum of water ice <90KNote : Blue shift in the solid phase

24. VUV Spectrum of carbon dioxide ice <90KNote : Blue shift in the solid phase

25. Comparison of gas and solid phase MethylamineNote absence of low lying bands in solid phase

26. Some ‘first’ conclusions • Can not use gas phase data to predict position of electronic bands in the ice phase. • Some electronic states are ‘missing’ in solid phase spectra. • Cross sections ( hence photodissociation rates) change from gas to solid.

27. SO2 Morphology and temperature • ‘Fast’ deposition at 25 K No vibrational structure  Indicates amorphous ice • Annealed to/deposited at 90 K vibrational structure & evidence of Davydov splitting  Indicates crystalline ice • Slow’ deposition at 25 K Weak vibrational structure evidence of some degree of crystallinity !

28. SO2 • Conclusions • Rate of deposition is important in determining ice morphology. • May form mixed amorphous/crystalline ice. • Crystallinity is not always a signature of temperature or thermal history !

29. Ammonia gas vs solid (25K)

30. Ammonia Different T

31. The band at 194 nm is indicative of ‘exciton’ formation

32. Ammonia ice in the IR • 1060 cm-1 peak is evidence of crystalline structure. • 1070 cm-1 peak is due to amorphous ice. • The 1100 cm-1 peak indicative of exciton measure of grain boudaries

33. Deposited at 25 K Amorphous: Disordered structure, thermodynamically unstable Annealed to >65 K Semi/polycrystalline: More ordered structure with crystallite & amorphous mix, thermodynamically stable Deposited >65 K Polycrystalline: many small crystallites, large number of grain boundaries, thermodynamically stable Deposited at >90 K Crystalline: Large crystallites, few grain boundaries, thermodynamically stable

34. Ammonia • Both UV and IR show features that are characteristic of exciton formation • Complex ice morphology formation of regions of crystalline ice in an ‘amorphos sea’ • Crystallites • Structure is random/statistical. Each sample is different ! Depends on deposition time.

35. Studies in chemical processing of astrochemical ices Ices may be processed by UV light or cosmic rays in the ISM On planetary surfaces interaction with ions from the planetary magnetosphere e.g. Moons of Jupiter and Saturn

36. Ion Interactions with Planetary Surfaces Nature 292, 38 - 39 (02 July 1981) Evidence for sulphur implantation in Europa's UV absorption band Arthur L. Lane, Robert M. Nelson & Dennis L. Matson The International Ultraviolet Explorer (IUE) spacecraft has obtained observations of the galilean satellites over the past 2 years ………… …………… We report here the discovery of an absorption feature at 280 nm in Europa's reflection spectrum. Observations with the IUE show that this absorption is strongest on Europa's trailing hemisphere (central longitude 270°). We identify the feature as an SO2 absorption band and hypothesize that SO2 may form when energetic jovian magnetospheric sulphur ions are injected into Europa's water-ice surface. Nature388, 45 - 47 (1997) Detection of ozone on Saturn's satellites Rhea and Dione K. S. NOLL, T. L. ROUSH, D. P. CRUIKSHANK, R. E. JOHNSON & Y. J. PENDLETON The satellites Rhea and Dione orbit within the magnetosphere of Saturn, where they are exposed to particle irradiation from trapped ions. A similar situation applies to the galilean moons Europa, Ganymede and Callisto, which reside within Jupiter's radiation belts. All of these satellites have surfaces rich in water ice1, 2……. …………… Here we report the identification of O3 in spectra of the saturnian satellites Rhea and Dione. The presence of trapped O3 is thus no longer unique to Ganymede, suggesting that special circumstances may not be required for its production. Nature373, 677 - 679 (1995) Detection of an oxygen atmosphere on Jupiter's moon Europa D. T. Hall, D. F. Strobel, P. D. Feldman, M. A. McGrath & H. A. Weaver EUROPA, the second large satellite out from Jupiter, is roughly the size of Earth's Moon, but unlike the Moon, it has water ice on its surface1. …….. …………. Here we report the detection of atomic oxygen emission from Europa, which we interpret as being produced by the simultaneous dissociation and excitation of atmospheric O2 by electrons from Jupiter's magnetosphere. Europa's molecular oxygen atmosphere is very tenuous, with a surface pressure about 10-11 that of the Earth's atmosphere at sea level. Chemistry of Planets

37. Ion v Photon irradiation • Photoabsorption of a photon interact with single target (selection rules) • Dissociation, ionisation, excitation • Secondary electrons • Penetration depth depends on the optical properties of the material • Ions interact with many atoms/molecules along the ion tracks • Dissociation, ionisation, excitation • Dislocations • Primary, secondary… knock-on particles • Secondary, tertiary… electrons • Sputtering • Implantation (reactive species) • Penetration depth depends on the ion energy and mass and the stopping power of the ice Chemistry of Planets

38. Experiments performed at ECRIS QUB • 9.0 – 10.5 GHz Electron Cyclotron Resonance Ion Source at QUB Chemistry of Planets

39. dOH 13CO2 Results: FTIR Spectroscopy Redshift and broadening of the H2O O-H stretching band Chemistry of Planets

40. CO2 H2CO3 H2O H2CO3 CO H2CO3 CO3 H2O CO2 H2CO3 H2CO3 H2O H2CO3 No CO3 CO H2O Proton irradiation of H2O:CO2 100 keV H+ 5 keV H+ Chemistry of Planets

41. Stability and Reactivity of Ozone in Astrochemical Ices

42. Bio-signatures Molecules that can be used to detect life elsewhere – exoplanets >> Ozone (O3) >> Nitrous oxide (N2O) These molecules are selected from the planet that already supports organic life form… EARTH !.

43. Why Ozone? • Essential component of any atmosphere capable of sustaining life • Strong evidence that the planet can support life - if not the existence of life itself • Identified in planetary, satellites surfaces. Ozone chemistry is possible in these ices. • DARWIN mission --- Biomarker?

44. Ozone from oxides of nitrogen • Ozone produced from the irradiation of solid oxides of nitrogen, like N2O and NO2. Dissociation pathway N2O  N2 + O (1D or 3P) NO2NO + O Formation pathway O + O  O2 O + O2 O3

45. e- irradiation of N2O >> Steady ozone growth >> No dissociation or reduction >> Less dose -- less NxOy molecules Will there be any change with the higher dose irradiation?

46. Presence of N2O5 in N2O ice How are the other new molecules produced?

47. Reactions for N2O ice N2O+ O(1D)  (NO)2 NO + O  NO2 2NO2 + O3 N2O5 + O2 Will it be the same for an NO2 ice?

48. Conclusion • Ozone is highly stable in a pure oxygen ice. • No reaction or significant amount of dissociation in a CO2 ice. • But in the presence of oxides of nitrogen, ozone that is produced reacts with NxOy molecules.

49. Implications • Ozone that is produced by the action of energetic particles in astrochemical ices take part in reactions as observed in the Earth’s stratosphere. • Therefore ozone not only acts as a biomarker but also an active reactant in the icy surfaces similar to Earth’s troposphere/stratosphere.

50. Questions for Astrochemistry • Spectral analysis of ices is a useful tool for identifying ice morphology both in the IR and UV. So need more spectroscopic studies of ices under ISM conditions • Experimentally it is vital that different experiments are calibrated against one another such that the morphology of the ices used are compatible.