1. A3: DESIREE Design and examples of planned experiments Belfast, July 1, 2003 Henning Schmidt, Stockholm University ( D ouble E lectro S tatic I on R ing E xp E riment)

2. Stockholm Low-Energy facilities: zDESIREE Double ElectroStatic Ion Ring ExpEriment. zCRYSIS (EBIS source for very high charge states e.g. U 70+ ) zECR ion source for intense beams of moderately high charge states.

3. Outline zThe DESIREE project yMotivation: Mutual Neutralization yBrief technical description yPlanned experiments xAMO Physics Example: Diffuse interstellar absorption bands xBiomolecules Example: ‘Electron Capture Dissociation’ zSummary

4. Plasma environments: zThe degree of ionization is a determining factor for the ongoing chemistry. Processes that affect this parameter are therefore crucial. zElectron-Ion recombination: yX + + e -  X + h (atomic recombination) AB + + e -  A + B (dissociative recombination) zMutual Neutralization : yX + + Y -  X + Y A - + BC +  A + BC or A + B + C

5. DESIREE Double Electro- Static Ion Ring ExpEriment 1 m zDouble-walled vacuum vessel yOuter tank 300K - Inner tank 15K yCooling by cryogenerators zExpected vacuum in inner part y300 K: <10 -11 mbar y15 K: Density reduced by order(s) of magnitude Ion sources: Plasma Ion Sources Sputter Source (Negative Ions) ESI Source (Biomolecules) ECRIS (Highly Charged Ions)

6. 1 m Position- sensitive detector ELISA DESIREE

7. Merged-beams experiments zLongitudinally: Kinematical compression zTransversely: Ion optics determines: < 1 eV seems feasible. zCan beam cooling be developed? Relative velocity definition: zExample: MN H - +H 2 + E=10 keV/amu, E rel =1 eV, A max =1 cm 2,  =1.6. 10 -14 cm 2 (COB), I + =I - =100 nA, L=80 cm: 44 s -1 zBackground rate is similar - The key point is that in MN there are (at least) two neutrals in coincidence!! zHow about experiments with Biomolecules? Count Rate estimates: R  N:In above example N=4. 10 6. Feasible for ESI with trap

8. Three special features of DESIREE: zDouble-ring structure: yMerged beams positive/negative ion collisions. zCryogenic system: yExtremely good vacuum  Long storage lifetime. yInternally cold molecular ions. zElectrostatic confinement: yHigh mass-to-charge ratios (i.e. Biomolecules). yAbsence of magnetic-field mixing in lifetime measurements

9. Examples of proposed experiments at the DESIREE facility: zAtoms and ‘Small’ Molecules: ySingle-Ring Experiments xLifetime measurements of metastable ions (He -, C 60 q+,…) xLASER spectroscopy of atomic/molecular ions (e.g. C n - ) yMerged-Beams Experiments xMutual Neutralization Collisions Fundamental systems (e.g. H - +H 2 +  …..) Astrophysical plasmas (e.g. C n - +H 3 +, H 3 O +,….) Atmospherical ion chemistry. xCollisions involving fullerenes (C 60 q+ +C 60 -, Ar 8+ +C 60 -,….)

10. zBiomolecules: ySingle-Ring Experiments (already pursued at ELISA) xLifetime and stability (J.U.Andersen et al, to be published) xLASER spectroscopy (e.g. GFP: S.B.Nielsen et al PRL 87, 228102 (2001)) yMerged-Beams Experiments xElectron Capture Dissociation in Negative/Positive ion collisions xCoulombic explosions induced by highly charged ions zBiomolecules: Examples of proposed experiments at the DESIREE facility: zBiomolecules: ySingle-Ring Experiments (already pursued at ELISA) xLifetime and stability (J.U.Andersen et al, to be published) xLASER spectroscopy (e.g. GFP: S.B.Nielsen et al PRL 87, 228102 (2001))

11. Electron Capture Dissociation zECD is important in protein sequencing because it breaks other bonds than those accessed in collision-induced dissociation. zECD is studied by introducing electrons in the plasma of FT-ICR mass spectrometer. No control of electron impact energy. zUsing simple negative ion to carry the electron, low (even below zero) and well-controlled relative energy is obtained.

12. Electron-transfer 10 a 0  10 a 0

13. Area of impact for ’distant’ collisions. zExperimental indication of distant collision: yDetection of neutral at proper time in relation to the arrival of the biomolecule(ar fragments)

14. Summary: zDESIREE can be built! zWe can do new AMO physics in single-ring and particularly in merged-beams configuration (Mutual Neutralization) zSpectroscopy and lifetime measurements for biomolecular ions - ELISA z’ECD’ like processes and HCI-biomolecular ion interaction in merged-beams - DESIREE unique The End!

15. DESIREE People: zPrimary investigator: Ö. Skeppstedt zDesign group: K-G Rensfelt, M. Andersson, L. Bagge, H. Danared, J. Jensen, L. Liljeby, H.T. Schmidt, K. Schmidt, A. Simonsson zContributors to the Scientific Programme: H. T. Schmidt, H. Cederquist, T. Hansson, J. Jensen, M. Larsson, S. Mannervik, P. vd Meulen, J. Pettersson. P. Royen, E. Uggerud, R. A. Zubarev New Leif? New Life!