1. New LEIF I3 Transnational access to ELISA
Department of Physics and Astronomy
University of Aarhus, Denmark
Steen Brøndsted Nielsen

3. ELISA = ELectrostatic Ion Storage ring Aarhus
Commisioned in 1999
ENTIRELY ELECTROSTATIC
Advantages:
Store ions of fixed charge and energy with arbitrary mass
Useful for study of heavy ions: fullerenes and biomolecules
Combined with an electrospray ion source and a multipole ion trap to accumulate the ions for injection into ELISA.
Another is operating in Japan

4. ELectrostatic Ion Storage Ring Aarhus (ELISA)
Laser pulse
Laser power meter
Ion bunch
Nd:YAG
Magnet
Injection
Micro-channel plate
detector
1 m
Accelerator with
electrospray ion source
S.P. Møller, NIM A 394, 281 (1997).
J.U. Andersen, J.S. Forster, P. Hvelplund, T.J.D. Jørgensen, S.P Møller, S.B. Nielsen, U.V. Pedersen, S. Tomita, and H. Wahlgreen, Rev. Sci. Instrum. 73, (2002).

5. ION SOURCES FOR ELISA Electrospray ionization:
biomolecules, fullerenes, metal-ligand complexes, solvated ions, etc.
(Collaboration with Caen and Stockholm,
Andersen et al., Eur. Phys. J. D, in press)
Electron Cyclotron Resonance (ECR):
fullerenes
(Collaboration with Caen and Stockholm)
Plasma ion source:
fullerenes, atomic and small molecular ions
Sputter ion source:
metal clusters, atomic and small molecular anions

6. ELECTROSPRAY ION SOURCE
Tube lens
Octapole
Skimmer
Lenses
ESI needle
4kV
Acceleration tube
10-6 mbar
1 mbar
10-3 mbar
10-5 mbar
Heated
capillary
22-pole ion trap

7. LASERS AVAILABLE AT ELISA
10 Hz pulsed Nd:YAG laser: 1064 nm
Harmonic generation: 532 nm, 355 nm, 266 nm
OPO pumped with 355 nm, 430 – 630 nm
Dye laser pumped with 532 nm
10 Hz pulsed alexandrite laser: 720 – 800 nm
Harmonic generation and Raman shifting: 200 nm – 2 mm

8. Biomolecular ions stored so far in ELISA:
Protonated amino acids and peptides
Proteins (lysozyme, cytochrome c)
Protein chromophores
Nucleotides and oligonucleotides
Protoporphyrin and heme ions

9. ELISA experiments:
Collisional cross sections, geometrical size of molecule
Radiative cooling (emission from infrared active vibrations)
Lifetimes after photon absorption:
statistical decay processes
excited state lifetimes, e.g. triplet states
Absorption spectroscopy
Ion-electron interactions:
dissociative recombination
anion-electron scattering

10. AARHUS PROJECTS BIOPHYSICS Photophysics of DNA and RNA.
Spectroscopy of ionic biomolecules in vacuo, e.g., the isolated chromophore from the Green Fluorescent Protein and derivatives.
Lifetimes of protonated amino acids and peptides after UV irradiation.
Cooling of protonated amino acids by emission of IR photons.
Triplet lifetime and triplet quantum yields of protoporhyrin and heme ions after laser excitation.
MATERIALS SCIENCE
Electronic structure of organic radical cations used in organic conductors.

11. J.U. Andersen et al., Eur. Phys. J. D., in press.
1/t decay
radiative cooling
J.U. Andersen et al., Eur. Phys. J. D., in press.