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BigLight for Ion Cyclotron Resonance. Nick Polfer University of Florida Gainesville, FL. Experimental. Measure vibrational spectra of mass-selected ions. ICR trap ultra-high vacuum ( no collisional relaxation ) long trapping (minutes) gentle trapping (keep fragile species intact)
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BigLight for Ion Cyclotron Resonance Nick Polfer University of Florida Gainesville, FL
Experimental Measure vibrational spectra of mass-selected ions • ICR trap • ultra-high vacuum (no collisional relaxation) • long trapping (minutes) • gentle trapping (keep fragile species intact) • high resolution and ion manipulation Valle, Eyler, Oomens, et al.. Rev. Sci. Instrum.2005, 76, 23103.
Scientific impact Annual number of publications from FEL facilities FELIX, CLIO and FEL-SUT First FEL IR spectrum D2O D2O D2O Polfer, Oomens, Mass Spectrom. Rev. 2009, 28, 468.
Scientific impact ctd’ Oomens (FELIX) D2O Maitre (CLIO) D2O D2O D2O D2O Limited by FEL beam time
Present experiments A plethora of ionic systems can be considered. Many ionization sources developed decades ago. Astrophysical relevance: polyaromatic hydrocarbons (PAHs) Catalysis: metal clusters Mechanisms of reactions: reaction products Solvation, structure: biomolecules D2O D2O D2O D2O D2O D2O D2O
Astrophysical relevance Comparison of laboratory IR spectra of PAHs with unidentified IR (UIR) bands from interstellar nebulae D2O D2O D2O D2O Mixture of neutral and cationic PAHs BUT, no idea which ones… D2O Joblin, et al. APS Conference Series
Reaction products b4+ fragment Pentapeptide: Xxx-Xxx-Xxx-Xxx-Xxx
Different IR spectra – a lot of chemistry • diagnostic vibrations yielding chemically important information • in particular, the location of the charge and the presence (or absence) of chemical moieties Polfer, Oomens, Suhai, Paizs; JACS2007, 129, 5887.
internal H+ transfer Solvation Gas-phase – neutral/canonical + - D2O D2O Solution phase - zwitterionic D2O D2O For tryptophan: 5,6 MeOH D2O D2O D2O Blom, Compagnon, Polfer, von Helden, Meijer, Suhai, Paizs, Oomens; JPCA, 2007, 111, 7309.
Structure of proteins D2O D2O • amide I (C=O stretch) 1660 cm-1 (in solution 1648-1658 cm-1 for -helix) D2O D2O D2O • amide II (N-H bend) 1535 cm-1 (in solution 1540-1550 cm-1 for -helix) D2O Oomens, Polfer, Moore, van der Meer, Marshall, Eyler, Meijer, von Helden; PCCP 2005, 7, 1345 .
Future experiments Manufacturing other product ions (e.g. ion/ion reactions) Biomolecules: solvation Far-IR for PAH cations Biomolecules: amyloid aggregation D2O D2O D2O D2O D2O D2O
Far-IR PAHs Far-IR spectra are better ‘fingerprint’ of PAHs D2O D2O Astrophysical data: Herschel Space Observatory, and the forthcoming Stratospheric Observatory for Infrared Astronomy (SOFIA) and Atacama Large Millimeter Array (ALMA) astronomical facilities D2O D2O D2O D2O D2O Zhang, Guo, Colarusso, Bernath; Science1996, 274, 582.
Early stages in amyloid aggregation IR spectrum secondary structure (-sheet) D2O D2O D2O D2O D2O D2O D2O Can ‘fish out’ amyloid aggregates in a mass spectrometer
The alternative Benchtop IR lasers: idler 2500 – 4000 cm-1 (2.5 – 4 m) 30-50 mW (cw) c.f. pulsed OPO lasers 10 mJ for idler (10 ns) (10 Hz) D2O Mid-IR: (AgGaSe2 crystal) 1400 – 2100 cm-1 (7.14 – 4.76 m) 0.4 mJ at 1600 cm-1 [1] 0.075 mJ at 1000 cm-1 [2] D2O D2O [1] Gerhards, Opt. Commun. 2004, 241, 493. [2] Hammer, et al. J. Chem. Phys.2005, 122, 244301.
Versatile instrumentation FEL IR Linear ion trap (CID, ETD, ion reactions) Quad mass filter Magnet (e.g. 4.7, 7 T) ESI D2O IR Cluster source D2O FEL EI ICR cell D2O D2O Transfer guide D2O D2O Cryogentically cooled Gerlich trap (many poles) UV Dye laser
