Efficient, highly selective laser isotope separation of carbon-13

We recently demonstrated an original approach to highly selective laser isotope separation of carbon-13 that employs vibrational overtone pre-excitation of CF3 H together with infrared multiphoton dissociation [O.V. Boyarkin, M. Kowalczyk, T.R. Rizzo, J. Chem. Phys. 118, 93 (2003)]. The practical implementation of this approach was complicated by the long absorption path length needed for the overtone excitation laser beam. In the present work, we employ a low overtone level for the pre-excitation that shortens this pathway, facilitating engineering of the process. We propose an optimal configuration of the isotope separation scheme and consider a realistic example of a separation unit for isotopic enrichment of carbon-13 to 94–98%. The photon energy expenditure of 97 eV per separated atom is much lower than that of the current commercial laser technology, making this process economically feasible

Conformational distribution of bradykinin [bk+2H]2+ revealed by cold ion spectroscopy coupled with FAIMS

We employ Cold Ion Spectroscopy (CIS) in conjunction with high-Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) to study the peptide bradykinin in its doubly protonated charge state ([bk+2H]2+). Using FAIMS we partially separate the electrosprayed [bk+2H]2+ ions into two conformational families and selectively introduce one of them at a time into a cold ion trap mass spectrometer, where we probe them by UV photofragment spectroscopy. Although the two conformational families have distinct electronic spectra, some cross-conformer contamination can be observed under certain conditions. We demonstrate that this contamination comes from isomerization of ions energized during and/or after their separation and not from incomplete separation of the initially electrosprayed conformations in the FAIMS stage. By varying the injection voltage of the ions into our mass spectrometer we can intentionally induce isomerization to produce what seems to be a gas phase equilibrium distribution of conformers. This distribution is different from the one produced initially by electrospray, indicating that some of the conformers are kinetically trapped and may be related to conformers that are more favored in solution

Cold Spectroscopy of Metal Ion-Crown Ether Complexes in the Gas Phase

Seventh International Conference on Advanced Vibrational Spectroscopy (ICAVS-7), 2013年8月25日-30日, 神戸国際会議

UV and IR Spectroscopic Studies of Cold Alkali Metal Ion-Benzo Crown Ether Complexes in the Gas Phase

International Symposium on Molecular Spectroscopy, from June 18 to June 22, 2012, at Ohio State University, in Columbus, Ohio, US

UV and IR spectroscopic studies of metal ion-crown ether complexes in the gas phase and on gold surface

Gordon Research Conferences –Molecular & Ionic Clusters, from April 27 to May 2, 2014, Renaissance Tuscany Il Ciocco, in Lucca (Barga), Ital

UV and IR Spectroscopic Studies of Cold Alkali Metal Ion-Benzo Crown Ether Complexes in the Gas Phase

International Symposium on Molecular Spectroscopy, from June 18 to June 22, 2012, at Ohio State University, in Columbus, Ohio, US

UV AND IR SPECTROSCOPIC STUDIES OF COLD ALKALI METAL ION-BENZO CROWN ETHER COMPLEXES IN THE GAS PHASE

Author Institution: Department of Chemistry, Faculty of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan; Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne, Lausanne CH-1015, Switzerland; Department of Chemistry, Faculty of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan; Department of Chemistry, Faculty of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan; Department of Chemistry, Faculty of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan; Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne, Lausanne CH-1015, SwitzerlandWe measured UV photodissociation and IR-UV double-resonance spectra of benzo-crown ether complexes with alkali metal ions (Li$^{+}$, Na$^{+}$, K$^{+}$, Rb$^{+}$, and Cs$^{+}$) in a cold, 22-pole ion trap nderline{\textbf{133}}(31), 12256 July 2011.}. All the complexes show a number of vibronically resolved UV bands in the 36000-38000 cm$^{-1}$ region. We used the IR-UV spectra in the CH stretching region to distinguish peaks in the UV spectra that belong to different conformers. The use of density functional theory allows us to determine the conformation of the complexes

UV and IR spectroscopic studies of alkali metal ion-crown ether complexes in the gas phase and on gold surface

Gordon Research Conferences –Molecular & Ionic Clusters, from April 27 to May 2, 2014, Renaissance Tuscany Il Ciocco, in Lucca (Barga), Ital

Cryogenically cooled octupole ion trap for spectroscopy of biomolecular ions

We present here the design of a linear octupole ion trap, suitable for collisional cryogenic cooling and spectroscopy of large ions. The performance of this trap has been assessed using ultraviolet (UV) photofragmentation spectroscopy of protonated dipeptides. At the trap temperature of 6.1 K, the vibrational temperature of the ions reaches 9.1 K, although their estimated translational temperature is similar to 150 K. This observation suggests that, despite the significant translational heating by radio-frequency electrical field, vibrational cooling of heavy ions in the octupole is at least as efficient as in the 22-pole ion traps previously used in our laboratory. In contrast to the 22-pole traps, excellent radial confinement of ions in the octupole makes it convenient for laser spectroscopy and boosts the dissociation yield of the stored ions to 30%. Overlap of the entire ion cloud by the laser beam in the octupole also allows for efficient UV depletion spectroscopy of ion-He clusters. The measured electronic spectra of the dipeptides and the clusters differ drastically, complicating a use of UV tagging spectroscopy for structural determination of large species. (C) 2014 AIP Publishing LLC