1. JRA3: Cold and Complex (Biomolecular) Targets Why study interaction of HCI with biomolecular targets? Basic physics: large energy transfer in a single collision! Applied physics: HCI as secondary products, e.g. in radiation therapy Why “cold” targets? All molecules in one electronic (ground-) state Possibility of recoil momentum spectroscopy Co-ordinators: Thomas Schlathölter and Reinhard Morgenstern

2. Tasks and Volunteers A. Solid biomolecular targets, CEA/Caen (Huber, Lebius) B. Ionic biomolecular targets NUI / Maynoth (O’Neill, v.d. Burgt) QUB /Belfast (Greenwood, Williams, McCullough, OUL /London (Mason), KVI /Groningen (Schlathölter, Morgenstern) C. Neutral gasphase biomolecular targets CUB / Bratislava (Matejcik), OUL /London (Mason), UIBK /Innsbruck (Scheier, Märk), LCAR /Toulouse (Moretto Capelle) D. Ultracold neutral targets (nanodroplets, MOT’s) UBI /Bielefeld (Stienkemeier, Werner), OUL /London (Mason), KVI /Groningen (Schlathölter, Morgenstern) E. Datareduction and analysis UBI /Bielefeld (Werner),

3. A. Solid biomolecular targets In the case of a nucleic bases, a compressed powder is used as a 'solid' target, which can be bombarded with ions of different charges and energies, and at different incidence angles. Fragmentation spectra are analysed with mass-spectrometric methods. DeOxyAdenosine

4. inset part magnified by a factor 10 Huber et al, Caen Dependence of the fragmentation of thymidine on the incidence angle (m=241)

5. B. Ionic biomolecular targets Adaption of MALDI techniques Desorption laser Desorption of ions and neutrals Laser QUB arrangement to study neutral targets Pulsed ion beam

6. the principle to get an ionic target MALDI sample (located in a trap endcap) laser pulse matrix bio molecules 3 rd or 4 th harmonic of our Nd:YAG-laser (355 or 266 nm) Quantel Brilliant pulse length: ~5 ns frequency: 50 Hz fluence: up to 200 mJ/cm 2 @ 1064 nm. MALDI and an electrostatic trap trapping and cooling of desorbed ions expanding plume (neutrals and ions)

7. trapped ions as target for HCI/fs-laser pulses ECRIS or fs-laser YAG laser trap Einzel lens MALDI sample reflectron detector electrostatic analyzer ions TOF analysis by means of a FAST P7888 TDC (1ns resolution, 1ns deadtime, 1 GHz) Several events per sweep: possibility of coincidence experiments fields are switched off for MCI bunch passage!

8. measurement cycle 1) laser desorbed ionic biomolecules are introduced from one electrode of the trap trap/TOF tandem leads to high mass resolution which can be extended to high m/q values allowing for the study of large biomolecules. 1) reflectron 2,3) 3)the trapping potentials are switched of 2)ions are accumulated and cooled 4) 4)a pulse of MCI passes the trapping region through the ring electrode 6)ions pass a reflectron TOF spectrometer 5) 5) a dc pulse applied to the second end cap extracts molecular ions and fragments

9. C. Neutral gasphase bio-molecular targets Target production via evaporation possible for DNA or RNA building bloks like thymine or uracil Problem: Are the molecules in their electronic groundstate? Approach for a solution: Check via reactions which are sensitive for electronic state Example: H-loss or fragmentation in low energy attachment reactions

10. Electron attachment (Scheier, Märk) Thymine Uracil 01234 0 1 2 3 4 Electron energy (eV) Cross section (10 -20 m 2 ) (×0.33) Glycine M + e‾ → (M-H)‾ + H P. Scheier, T. Märk

11. D. Production and manipulation of ultracold targets Capture in magneto-optical traps (MOT’s) sympathetic cooling of molecules in a MOT Capture of biomolecules in He nano droplets

12. Ultra cold Na target in a Magneto Optical Trap (MOT) near resonance laser light to trap and cool Na atoms: Load from background vapor 10 6 –10 7 Sodium atoms sub mm size cloud 200-300  K (<30 neV!) laser light + magnetic quadrupole field = MOT

13. TOF and recoilspectroscopy of O 6+ + Na collisions -12-10-8-6-4-2024 0 10 20 30 40 50 60 70 80 90 100 110 transversal momentum longitudinal momentum -12-10-8-6-4-2024 0 10 20 30 40 50 60 70 80 90 100 110 transversal momentum longitudinal momentum Na 4+ -12-10-8-6-4-2024 0 10 20 30 40 50 60 70 80 90 100 110 transversal momentum longitudinal momentum Na 3+ Na 2+

14. Apparatus for He nanodroplet studies Toennies et al, Physics Today, Feb. 2001, 31-37

15. Helium droplet beam machine Fakultät für Physik

16. Formation of large molecular complexes in helium droplets M. Wewer and F. Stienkemeier, Phys. Rev. A 37, 2002 Spectroscopy of excitonic transitions in PTCDA nanostructures at 380 mK

17. Laser induced fluorescence spectrum of PTCDA (a) in a nanodroplet (b) in the gasphase F. Stienkemeier and A.F. Vilesov J. Chem. Phys.115 (2001) 10119

18. E. Data reduction and analysis A non-trivial task! High-dimensional parameter space! (up to 30-40 parameters per collision event) Pattern recognition Fitting procedures based on e.g. maximum entropy methods

19. Xe 20+, 400 keV O 2+, 40 keV Huber et al, Caen NIM B 205 (2003) 666–670 Fragmentation of thymidine by ions with high and low charge