Yutaka Matsumi

Bio: Yutaka Matsumi is an academic researcher from Nagoya University. The author has contributed to research in topics: Photodissociation & Laser-induced fluorescence. The author has an hindex of 37, co-authored 215 publications receiving 4730 citations. Previous affiliations of Yutaka Matsumi include Hokkaido University & University of Southern Denmark.

Atmospheric chemistry of cyclohexanone: UV spectrum and kinetics of reaction with chlorine atoms

Abstract: Absolute and relative rate techniques were used to study the reactivity of Cl atoms with cyclohexanone in 6 Torr of argon or 800 950 Torr of N2 at 295 2 K. The absolute rate experiments gave k(Cl + cyclohexanone) = (1.88 0.38) 10 10, whereas the relative rate experiments gave k(Cl + cyclohexanone) = (1.66 0.26) 10 10 cm3 molecule 1 s 1. Cyclohexanone has a broad UV absorption band with a maximum cross section of (4.0 0.3) 10 20 cm2 molecule 1 near 285 nm. The results are discussed with respect to the literature data.

Optical Properties and Chemical Compositions of Iodine-Containing Aerosols Produced from the Atmospheric Photolysis of Methylene Iodide in the Presence of Ozone

Abstract: Optical properties of iodine-containing aerosols that were produced by ultraviolet photoirradiation of a mixture gas of CH 2 I 2 and O 3 with dry air diluent have been measured using a nephelometer, a particle soot absorption photometer and a cavity ring-down spectrometer. Single scattering albedo of iodine aerosols was determined to be 0.96 ± 0.01 at around 530 nm. Chemical compositions of the aerosols associated with particle size in the range of 0.2-1 μm was measured using a laser-ionization single-particle aerosol mass spectrometer. Positive and negative ion signals of iodine and iodine oxides, IO n (n = 0-4), I 2 O n (n = 0-6), and I 3 O n (n = 0-1), carbon-containing compounds and HOI were detected.

Accurate Determination of the Absolute Quantum Yield for O(1D) Formation in the Photolysis of Ozone at 308 nm

Abstract: Absolute O('D) quantum yield from the photodissociation reaction of O 3 at 308 nm should be determined accurately with high precision for its atmospheric significance. This is because it has been used as a reference in previous relative measurements to obtain the O( 1 D) quantum yields as a function of photolysis wavelength in the near-UV region. In this study, the near-UV pulsed-laser photolysis of O 3 with the direct detection of the O( 1 D) and O( 3 P) photofragments using a technique of vacuum UV laser-induced fluorescence has been applied to determine the absolute O('D) quantum yield from O 3 photolysis. The absolute O( 1 D) quantum yield at 308.0 nm at room temperature (298 ′ 2 K) is determined to be 0.804 ′ 0.048 (95% confidence interval), in which the uncertainty is much smaller than the values recommended for use in atmospheric studies. The O( 1 D) quantum yield values at photolysis wavelengths between 307 and 311.5 nm are also presented.

Photodissociation of Trimethylindium and Trimethylgallium on GaAs at 193 nm Studied by Angle-Resolved Photoelectron Spectroscopy

Abstract: The chemisorption and photodecomposition of trimethylindium (TMIn) and trimethylgallium (TMGa) on a GaAs(100) surface have been studied by means of angle-resolved X-ray and ultraviolet photoelectron spectroscopy. Increase in the substrate temperature from 150 to 300 K causes the In-C bond cleavage of the adsorbed TMIn to generate methyl radicals that react with Ga species in the substrate to form Ga-C bonds. The 193 nm irradiation of TMIn adsorbed on GaAs at 150 K induces the In-C bond cleavage. The carbon species desorb from the substrate. Irradiation at 351 nm causes no change in the X-ray photoelectron spectra of the adsorbed species. These results imply that photodissociation is not due to photoabsorption of the GaAs substrate but that of the adsorbed species on the substrate. Photoirradiation of 488 nm on TMIn adsorbed on GaAs at 150 K induces pyrolytic cleavage of the In-C bond.

Velocity map imaging of ions and electrons using electrostatic lenses: Application in photoelectron and photofragment ion imaging of molecular oxygen

Abstract: The application of electrostatic lenses is demonstrated to give a substantial improvement of the two-dimensional (2D) ion/electron imaging technique. This combination of ion lens optics and 2D detection makes “velocity map imaging” possible, i.e., all particles with the same initial velocity vector are mapped onto the same point on the detector. Whereas the more common application of grid electrodes leads to transmission reduction, severe trajectory deflections and blurring due to the non-point source geometry, these problems are avoided with open lens electrodes. A three-plate assembly with aperture electrodes has been tested and its properties are compared with those of grid electrodes. The photodissociation processes occurring in molecular oxygen following the two-photon 3dπ(3Σ1g −)(v=2, N=2)←X(3Σg −) Rydberg excitation around 225 nm are presented here to show the improvement in spatial resolution in the ion and electron images. Simulated trajectory calculations show good agreement with experiment and ...

Perfluoroalkyl and polyfluoroalkyl substances in the environment: Terminology, classification, and origins

Abstract: The primary aim of this article is to provide an overview of perfluoroalkyl and polyfluoroalkyl substances (PFASs) detected in the environment, wildlife, and humans, and recommend clear, specific, and descriptive terminology, names, and acronyms for PFASs. The overarching objective is to unify and harmonize communication on PFASs by offering terminology for use by the global scientific, regulatory, and industrial communities. A particular emphasis is placed on long-chain perfluoroalkyl acids, substances related to the long-chain perfluoroalkyl acids, and substances intended as alternatives to the use of the long-chain perfluoroalkyl acids or their precursors. First, we define PFASs, classify them into various families, and recommend a pragmatic set of common names and acronyms for both the families and their individual members. Terminology related to fluorinated polymers is an important aspect of our classification. Second, we provide a brief description of the 2 main production processes, electrochemical fluorination and telomerization, used for introducing perfluoroalkyl moieties into organic compounds, and we specify the types of byproducts (isomers and homologues) likely to arise in these processes. Third, we show how the principal families of PFASs are interrelated as industrial, environmental, or metabolic precursors or transformation products of one another. We pay particular attention to those PFASs that have the potential to be converted, by abiotic or biotic environmental processes or by human metabolism, into long-chain perfluoroalkyl carboxylic or sulfonic acids, which are currently the focus of regulatory action. The Supplemental Data lists 42 families and subfamilies of PFASs and 268 selected individual compounds, providing recommended names and acronyms, and structural formulas, as well as Chemical Abstracts Service registry numbers. Integr Environ Assess Manag 2011;7:513–541. © 2011 SETAC

Couplings between changes in the climate system and biogeochemistry

Abstract: Couplings Between Changes in the Climate System and Biogeochemistry Coordinating Lead Authors: Kenneth L. Denman (Canada), Guy Brasseur (USA, Germany) Lead Authors: Amnat Chidthaisong (Thailand), Philippe Ciais (France), Peter M. Cox (UK), Robert E. Dickinson (USA), Didier Hauglustaine (France), Christoph Heinze (Norway, Germany), Elisabeth Holland (USA), Daniel Jacob (USA, France), Ulrike Lohmann (Switzerland), Srikanthan Ramachandran (India), Pedro Leite da Silva Dias (Brazil), Steven C. Wofsy (USA), Xiaoye Zhang (China) Contributing Authors: D. Archer (USA), V. Arora (Canada), J. Austin (USA), D. Baker (USA), J.A. Berry (USA), R. Betts (UK), G. Bonan (USA), P. Bousquet (France), J. Canadell (Australia), J. Christian (Canada), D.A. Clark (USA), M. Dameris (Germany), F. Dentener (EU), D. Easterling (USA), V. Eyring (Germany), J. Feichter (Germany), P. Friedlingstein (France, Belgium), I. Fung (USA), S. Fuzzi (Italy), S. Gong (Canada), N. Gruber (USA, Switzerland), A. Guenther (USA), K. Gurney (USA), A. Henderson-Sellers (Switzerland), J. House (UK), A. Jones (UK), C. Jones (UK), B. Karcher (Germany), M. Kawamiya (Japan), K. Lassey (New Zealand), C. Le Quere (UK, France, Canada), C. Leck (Sweden), J. Lee-Taylor (USA, UK), Y. Malhi (UK), K. Masarie (USA), G. McFiggans (UK), S. Menon (USA), J.B. Miller (USA), P. Peylin (France), A. Pitman (Australia), J. Quaas (Germany), M. Raupach (Australia), P. Rayner (France), G. Rehder (Germany), U. Riebesell (Germany), C. Rodenbeck (Germany), L. Rotstayn (Australia), N. Roulet (Canada), C. Sabine (USA), M.G. Schultz (Germany), M. Schulz (France, Germany), S.E. Schwartz (USA), W. Steffen (Australia), D. Stevenson (UK), Y. Tian (USA, China), K.E. Trenberth (USA), T. Van Noije (Netherlands), O. Wild (Japan, UK), T. Zhang (USA, China), L. Zhou (USA, China) Review Editors: Kansri Boonpragob (Thailand), Martin Heimann (Germany, Switzerland), Mario Molina (USA, Mexico) This chapter should be cited as: Denman, K.L., G. Brasseur, A. Chidthaisong, P. Ciais, P.M. Cox, R.E. Dickinson, D. Hauglustaine, C. Heinze, E. Holland, D. Jacob, U. Lohmann, S Ramachandran, P.L. da Silva Dias, S.C. Wofsy and X. Zhang, 2007: Couplings Between Changes in the Climate System and Biogeochemistry. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.