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Title: Cold ion UV photofragmentation spectroscopy and dynamics (Invited)

Up to ten years ago, very little was known about the excited states of protonated amino acids isolated in the gas phase. From the experimental point of view, the study was hampered by the lack of ease of production of such species in sufficient density to apply photon-based techniques. With the development and widespread use of electrospray ionization sources coupled with modified or homebuilt mass spectrometers, there has been significant research into the spectroscopy of biomimetic and biologically relevant molecules. Besides, these species are floppy such that an efficient cooling is required to record clear spectroscopy. Warm protonated species display congested spectra. To extract precise spectroscopic information and avoid spectral congestion, the species need to be cooled down to less than 50 K. We present our latest results on the electronic spectroscopy of protonated phenylalanine and tyrosine on a large spectral domain (225-290 nm). These species are studied in a new simplified apparatus combining an electrospray ionization source, a cryogenically cooled quadrupole ion trap (∼10 K) and time-of-flight mass spectrometry. The role of proton transfer from the NH{sub 3}{sup +} moiety to the p-ring or to CO of the carboxylic acid group is evidenced by UV photofragment spectroscopy. This firstmore » step controls the fragmentation pathways, which strongly depend on the nature of the electronic excited states, i.e. ππ*, ππ*{sub CO} and πσ{sub NH3}.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4]
  1. CNRS, Aix Marseille Université, laboratoire de Physique des Interactions Ioniques et Moléculaires (PIIM) UMR 7345, 13397 Marseille cedex 20 (France)
  2. Université Paris Sud, CLUPS (Centre Laser de l'Université Paris Sud) LUMAT FR 2764, 91405 Orsay Cedex, France and CNRS, Université Paris Sud, Institut des Sciences Moléculaires d'Orsay (ISMO) UMR 8624, 91405 Orsay Cedex (France)
  3. CNRS, Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, UMR 7538, 93430 Villetaneuse (France)
  4. CNRS, Université Paris Sud, Institut des Sciences Moléculaires d'Orsay (ISMO) UMR 8624, 91405 Orsay Cedex (France)
Publication Date:
OSTI Identifier:
22390586
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1628; Journal Issue: 1; Conference: 29. International Symposium on Rarefied Gas Dynamics, Xi'an (China), 13-18 Jul 2014; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ABSORPTION SPECTROSCOPY; AMMONIA; CARBON MONOXIDE; CONTROL; COOLING; ELECTRONIC STRUCTURE; EQUIPMENT; EXCITED STATES; FRAGMENTATION; IONIZATION; PHENYLALANINE; PHOTONS; PROTONS; TIME-OF-FLIGHT METHOD; TRAPS; TYROSINE; ULTRAVIOLET SPECTRA