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Full-Text Articles in Social and Behavioral Sciences
Preliminary Validation Of Column-Averaged Volume Mixing Ratios Of Carbon Dioxide And Methane Retrieved From Gosat Short-Wavelength Infrared Spectra, David W. Griffith, G C. Toon, B Connor, R Sussmann, Thorsten Warneke, Nicholas M. Deutscher, Paul O. Wennberg, Justus Notholt, V Sherlock, J Robinson, O Uchino, C M. Roehl, I Morino, Debra Wunch, Janina Messerschmidt, Y Yoshida, M Inoue, M Rettinger
Preliminary Validation Of Column-Averaged Volume Mixing Ratios Of Carbon Dioxide And Methane Retrieved From Gosat Short-Wavelength Infrared Spectra, David W. Griffith, G C. Toon, B Connor, R Sussmann, Thorsten Warneke, Nicholas M. Deutscher, Paul O. Wennberg, Justus Notholt, V Sherlock, J Robinson, O Uchino, C M. Roehl, I Morino, Debra Wunch, Janina Messerschmidt, Y Yoshida, M Inoue, M Rettinger
Faculty of Science - Papers (Archive)
Column-averaged volume mixing ratios of carbon dioxide and methane retrieved from the Greenhouse gases Observing SATellite (GOSAT) Short-Wavelength InfraRed observation (GOSAT SWIR XCO2 and XCH4 ) were compared with the reference calibrated data obtained by ground-based high-resolution Fourier Transform Spectrometers (g-b FTSs) participating in the Total Carbon Column Observing Network (TCCON). Preliminary results are as follows: the GOSAT SWIR XCO2 and XCH4 (Version 01.xx) are biased low by 8.85 ±4.75 ppm (2.3±1.2 %) and 20.4±18.9 ppb (1.2±1.1 %), respectively. The standard deviation of the GOSAT SWIR XCO2 and XCH4 is about 1% after correcting the negative biases of XCO2 and …
Extensional And Colisional Magmatic Records In The Apiai Terrane, South-Southeastern Brazil: Integration Of Geochronological U-Pb Zircon Ages, Oswaldo Siga Junior, Miguel Angelo Stipp Basei, Allen P. Nutman, Kei Sato, Ian Mcreath, Claudia Regina Passarelli, Dunyi Liu
Extensional And Colisional Magmatic Records In The Apiai Terrane, South-Southeastern Brazil: Integration Of Geochronological U-Pb Zircon Ages, Oswaldo Siga Junior, Miguel Angelo Stipp Basei, Allen P. Nutman, Kei Sato, Ian Mcreath, Claudia Regina Passarelli, Dunyi Liu
Faculty of Science - Papers (Archive)
The aim of this work is the presentation of a synthesis of available geochronological data for the basement inliers and metavolcano-sedimentary sequences which occur in the southern part of the Apiai Terrane, south-southeastern Brazil. These data, especially those obtained during the last decade, have made substantial modifi cations to the tectonic scenario of south-southeastern Brazil with the recognition of the presence of extensional basins (continental rifts) with magmatism and sedimentation at the late Paleoproterozoic (1790 - 1750 Ma) and of the Mesoproterozoic (1600 - 1450 Ma). These processes started at the late Paleoproterozoic in the Betara, Perau and Apiai Mirim …
Methane Observations From The Greenhouse Gases Observing Satellite: Comparison To Ground-Based Tccon Data And Model Calculations, Robert Parker, Hartmut Boesch, Austin Cogan, Annemarie Fraser, Liang Feng, Paul Palmer, Janina Messerschmidt, Nicholas M. Deutscher, David W. Griffith, Justus Notholt, Paul O. Wennberg, Debra Wunch
Methane Observations From The Greenhouse Gases Observing Satellite: Comparison To Ground-Based Tccon Data And Model Calculations, Robert Parker, Hartmut Boesch, Austin Cogan, Annemarie Fraser, Liang Feng, Paul Palmer, Janina Messerschmidt, Nicholas M. Deutscher, David W. Griffith, Justus Notholt, Paul O. Wennberg, Debra Wunch
Faculty of Science - Papers (Archive)
We report new short-wave infrared (SWIR) column retrievals of atmospheric methane (X CH4) from the Japanese Greenhouse Gases Observing SATellite (GOSAT) and compare observed spatial and temporal variations with correlative ground-based measurements from the Total Carbon Column Observing Network (TCCON) and with the global 3-D GEOS-Chem chemistry transport model. GOSAT X CH4 retrievals are compared with daily TCCON observations at six sites between April 2009 and July 2010 (Bialystok, Park Falls, Lamont, Orleans, Darwin and Wollongong). GOSAT reproduces the site-dependent seasonal cycles as observed by TCCON with correlations typically between 0.5 and 0.7 with an estimated single-sounding precision between 0.4-0.8%. …
Retrieval Of Atmospheric Co2 With Enhanced Accuracy And Precision From Sciamachy: Validation With Fts Measurements And Comparison With Model Results, M Reuter, H Bovensmann, M Buchwitz, Jp Burrows, B Connor, Nicholas M. Deutscher, David W. Griffith, J Heymann, Gretchen Keppel-Aleks, Janina Messerschmidt, Justus Notholt, Christof Petri, J Robinson, O Schneising, V Sherlock, Voltaire A. Velazco, Thorsten Warneke, Paul O. Wennberg, Debra Wunch
Retrieval Of Atmospheric Co2 With Enhanced Accuracy And Precision From Sciamachy: Validation With Fts Measurements And Comparison With Model Results, M Reuter, H Bovensmann, M Buchwitz, Jp Burrows, B Connor, Nicholas M. Deutscher, David W. Griffith, J Heymann, Gretchen Keppel-Aleks, Janina Messerschmidt, Justus Notholt, Christof Petri, J Robinson, O Schneising, V Sherlock, Voltaire A. Velazco, Thorsten Warneke, Paul O. Wennberg, Debra Wunch
Faculty of Science - Papers (Archive)
The Bremen Optimal Estimation differential optical absorption spectroscopy (DOAS) (BESD) algorithm for satellite based retrievals of XCO 2 (the column-average dry-air mole fraction of atmospheric CO 2) has been applied to Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) data. It uses measurements in the O 2-A absorption band to correct for scattering of undetected clouds and aerosols. Comparisons with precise and accurate ground-based Fourier transform spectrometer (FTS) measurements at four Total Carbon Column Observing Network (TCCON) sites have been used to quantify the quality of the new SCIAMACHY XCO 2 data set. Additionally, the results have been compared to …
The Dirt On Assessing Post-Fire Erosion In The Mount Lofty Ranges: Comparing Methods, Rowena H. Morris, Solomon Buckman, Paul Connelly, Deirdre Dragovich, Bertram Ostendorf, Ross A. Bradstock
The Dirt On Assessing Post-Fire Erosion In The Mount Lofty Ranges: Comparing Methods, Rowena H. Morris, Solomon Buckman, Paul Connelly, Deirdre Dragovich, Bertram Ostendorf, Ross A. Bradstock
Faculty of Science - Papers (Archive)
Land managers are required to assess a range of environmental attributes prior to and after prescribed burning. Current environmental assessments vary depending on the organisation involved and the existing information about localised soil erosion. Auditing successful environmental assessments requires ongoing field monitoring to evaluate whether the magnitude and extent of predicted post-fire impacts are comparable. The impacts of post-fire erosion were assessed by the authors using the techniques of water sampling, sediment traps, erosion pins, laser scanning, photogrammetry and visual field assessment. Each data collecting method varies in its spatial and temporal reach in terms of monitoring landscape changes in …
The Australian Methane Budget: Interpreting Surface And Train-Borne Measurements Using A Chemistry Transport Model, A Fraser, C C. Miller, Paul Palmer, Nicholas M. Deutscher, Nicholas B. Jones, David W. Griffith
The Australian Methane Budget: Interpreting Surface And Train-Borne Measurements Using A Chemistry Transport Model, A Fraser, C C. Miller, Paul Palmer, Nicholas M. Deutscher, Nicholas B. Jones, David W. Griffith
Faculty of Science - Papers (Archive)
We investigate the Australian methane budget from 2005-2008 using the GEOS-Chem 3D chemistry transport model, focusing on the relative contribution of emissions from different sectors and the influence of long-range transport. To evaluate the model, we use in situ surface measurements of methane, methane dry air column average (XCH 4) from ground-based Fourier transform spectrometers (FTSs), and train-borne surface concentration measurements from an in situ FTS along the north-south continental transect. We use gravity anomaly data from Gravity Recovery and Climate Experiment to describe the spatial and temporal distribution of wetland emissions and scale it to a prior emission estimate, …
Airborne And Ground-Based Measurements Of The Trace Gases And Particles Emitted By Prescribed Fires In The United States, I R. Burling, R J. Yokelson, S K. Akagi, S P. Urbanski, C E. Wold, David W. Griffith, T J. Johnson, J Reardon, D R. Weise
Airborne And Ground-Based Measurements Of The Trace Gases And Particles Emitted By Prescribed Fires In The United States, I R. Burling, R J. Yokelson, S K. Akagi, S P. Urbanski, C E. Wold, David W. Griffith, T J. Johnson, J Reardon, D R. Weise
Faculty of Science - Papers (Archive)
We have measured emission factors for 19 tracegas species and particulate matter (PM2.5) from 14 prescribedfires in chaparral and oak savanna in the southwesternUS, as well as conifer forest understory in the southeasternUS and Sierra Nevada mountains of California. These arelikely the most extensive emission factor field measurementsfor temperate biomass burning to date and the only publishedemission factors for temperate oak savanna fuels. This studyhelps to close the gap in emissions data available for temperatezone fires relative to tropical biomass burning. Wepresent the first field measurements of the biomass burningemissions of glycolaldehyde, a possible precursor for aqueousphase secondary organic aerosol …
Electron Affinities, Well Depths, And Vibrational Spectroscopy Of Cis- And Trans-Hoco, Christopher J. Johnson, Michael E. Harding, Berwyck L. J Poad, John F. Stanton, Robert E. Continetti
Electron Affinities, Well Depths, And Vibrational Spectroscopy Of Cis- And Trans-Hoco, Christopher J. Johnson, Michael E. Harding, Berwyck L. J Poad, John F. Stanton, Robert E. Continetti
Faculty of Science - Papers (Archive)
We report vibrationally resolved photoelectron spectra of internally cold HOCO– and DOCO– anions at wavelengths near and well above the detachment threshold. These spectra are dominated by a strong Franck–Condon progression of three low-energy modes of the cis isomer, the first gas-phase measurement of these vibrations. Using highly resolved, near-threshold spectra we are able to reassign the electron affinities (EAs) of cis- and trans-HOCO to 1.51 ± 0.01 and 1.37 ± 0.01 eV, respectively. Using these EAs, well depths with respect to OH + CO are determined to be 1.07 ± 0.02 eV for trans-HOCO and 0.99 ± 0.02 eV …
Photoelectron-Photofragment Coincidence Spectroscopy In A Cryogenically Cooled Linear Electrostatic Ion Beam Trap, Christopher J. Johnson, Ben B. Shen, Berwyck L. J Poad, Robert E. Continetti
Photoelectron-Photofragment Coincidence Spectroscopy In A Cryogenically Cooled Linear Electrostatic Ion Beam Trap, Christopher J. Johnson, Ben B. Shen, Berwyck L. J Poad, Robert E. Continetti
Faculty of Science - Papers (Archive)
A cryogenically cooled linear electrostatic ion beam trap for use in photoelectron-photofragment coincidence (PPC) spectroscopy is described. Using this instrument, anions created in cold, low-dutycycle sources can be stored for many seconds in a ∼20 K environment to cool radiatively, removing energetic uncertainties due to vibrationally excited precursor anions. This apparatus maintains a well-collimated beam necessary for high-resolution fragment imaging and the high experimental duty cycle needed for coincidence experiments. Ion oscillation is bunched and phase-locked to a modelocked laser, ensuring temporal overlap between ion bunches and laser pulses and that ions are intersected by the laser only when travelling …
Communication: New Insight Into The Barrier Governing Co2 Formation From Oh + Co, Christopher J. Johnson, Berwyck L. Poad, Ben B. Shen, Robert E. Continetti
Communication: New Insight Into The Barrier Governing Co2 Formation From Oh + Co, Christopher J. Johnson, Berwyck L. Poad, Ben B. Shen, Robert E. Continetti
Faculty of Science - Papers (Archive)
Despite its relative simplicity, the role of tunneling in the reaction OH + CO → H + CO(2) has eluded the quantitative predictive powers of theoretical reaction dynamics. In this study a one-dimensional effective barrier to the formation of H + CO(2) from the HOCO intermediate is directly extracted from dissociative photodetachment experiments on HOCO and DOCO. Comparison of this barrier to a computed minimum-energy barrier shows that tunneling deviates significantly from the calculated minimum-energy pathway, predicting product internal energy distributions that match those found in the experiment and tunneling lifetimes short enough to contribute significantly to the overall reaction. …
Sources, Distribution, And Acidity Of Sulfate-Ammonium Aerosol In The Arctic In Winter-Spring, Jenny A. Fisher, Daniel J. Jacob, Q Wang, Roya Bahreini, C C. Carouge, M J. Cubison, Jack E. Dibb, Thomas Diehl, J L. Jimenez, E M. Leibensperger, Zifeng Lu, Marcel B.J Meinders, H. O T. Pye, Patricia K. Quinn, Sangeeta Sharma, David G. Streets, Aaron Van Donkelaar, R M. Yantosca
Sources, Distribution, And Acidity Of Sulfate-Ammonium Aerosol In The Arctic In Winter-Spring, Jenny A. Fisher, Daniel J. Jacob, Q Wang, Roya Bahreini, C C. Carouge, M J. Cubison, Jack E. Dibb, Thomas Diehl, J L. Jimenez, E M. Leibensperger, Zifeng Lu, Marcel B.J Meinders, H. O T. Pye, Patricia K. Quinn, Sangeeta Sharma, David G. Streets, Aaron Van Donkelaar, R M. Yantosca
Faculty of Science - Papers (Archive)
We use GEOS-Chem chemical transport model simulations of sulfate–ammonium aerosol data from the NASA ARCTAS and NOAA ARCPAC aircraft campaigns in the North American Arctic in April 2008, together with longer-term data from surface sites, to better understand aerosol sources in the Arctic in winter–spring and the implications for aerosol acidity. Arctic pollution is dominated by transport from mid-latitudes, and we test the relevant ammonia and sulfur dioxide emission inventories in the model by comparison with wet deposition flux data over the source continents. We find that a complicated mix of natural and anthropogenic sources with different vertical signatures is …
Calibration Of Tccon Column-Averaged Co2: The First Aircraft Campaign Over European Tccon Sites, Janina Messerschmidt, M. Geibel, T. Blumenstock, H. Chen, Nicholas Deutscher, A. Engel, D. Feist, C. Gerbig, M. Gisi, F. Hase, K. Katrynski, O. Kolle, J. Lavric, Justus Notholt, M. Palm, M. Ramonet, M. Rettinger, M. Schmidt, R. Sussmann, G. Toon, F. Truong, Thorsten Warneke, Paul Wennberg, Debra Wunch, I. Xueref-Remy
Calibration Of Tccon Column-Averaged Co2: The First Aircraft Campaign Over European Tccon Sites, Janina Messerschmidt, M. Geibel, T. Blumenstock, H. Chen, Nicholas Deutscher, A. Engel, D. Feist, C. Gerbig, M. Gisi, F. Hase, K. Katrynski, O. Kolle, J. Lavric, Justus Notholt, M. Palm, M. Ramonet, M. Rettinger, M. Schmidt, R. Sussmann, G. Toon, F. Truong, Thorsten Warneke, Paul Wennberg, Debra Wunch, I. Xueref-Remy
Faculty of Science - Papers (Archive)
The Total Carbon Column Observing Network (TCCON) is a ground-based network of Fourier Transform Spectrometer (FTS) sites around the globe, where the column abundances of CO2, CH4, N2O, CO and O2 are measured. CO2 is constrained with a precision better than 0.25% (1-σ). To achieve a similarly high accuracy, calibration to World Meteorological Organization (WMO) standards is required. This paper introduces the first aircraft calibration campaign of five European TCCON sites and a mobile FTS instrument. A series of WMO standards in-situ profiles were obtained over European TCCON sites via aircraft and …
Validation Of The Atmospheric Chemistry Experiment By Noncoincident Mkiv Balloon Profiles, Voltaire A. Velazco, G. Toon, J.-F. Blavier, A. Kleinbohl, G. Manney, W. Daffer, P. Bernath, K. Walker, C. Boone
Validation Of The Atmospheric Chemistry Experiment By Noncoincident Mkiv Balloon Profiles, Voltaire A. Velazco, G. Toon, J.-F. Blavier, A. Kleinbohl, G. Manney, W. Daffer, P. Bernath, K. Walker, C. Boone
Faculty of Science - Papers (Archive)
We have compared volume mixing ratio profiles of atmospheric trace gases measured by the Atmospheric Chemistry Experiment (ACE) version 2.2 and the MkIV solar occultation Fourier transform infrared spectrometers. These gases are H2O, O3, N2O, CO, CH4, HNO3, HF, HCl, OCS, ClONO2, HCN, CH3Cl, CF4, CCl2F2, CCl3F, COF2, CHF2Cl, and SF6. Due to the complete lack of close spatiotemporal coincidences between the ACE occultations and the MkIV balloon flights, we used potential temperatures and equivalent latitudes from analyzed meteorological fields to find comparable ACE and MkIV profiles. The results show excellent agreement for CH4, N2O, and other long‐lived gases but …
Atolls, Colin D. Woodroffe, Naomi Biribo
Atolls, Colin D. Woodroffe, Naomi Biribo
Faculty of Science - Papers (Archive)
No abstract provided.
Continental Aridification And The Vanishing Of Australia's Megalakes, Timothy J. Cohen, Gerald C. Nanson, John D. Jansen, B. G. Jones, Zenobia Jacobs, P Treble, David M. Price, Jan-Hendrik May, A Smith, Linda K. Ayliffe, John C. Hellstrom
Continental Aridification And The Vanishing Of Australia's Megalakes, Timothy J. Cohen, Gerald C. Nanson, John D. Jansen, B. G. Jones, Zenobia Jacobs, P Treble, David M. Price, Jan-Hendrik May, A Smith, Linda K. Ayliffe, John C. Hellstrom
Faculty of Science - Papers (Archive)
The nature of the Australian climate at about the time of rapid megafaunal extinctions and humans arriving in Australia is poorly understood and is an important element in the contentious debate as to whether humans or climate caused the extinctions. Here we present a new paleoshoreline chronology that extends over the past 100 k.y. for Lake Mega-Frome, the coalescence of Lakes Frome, Blanche, Callabonna and Gregory, in the southern latitudes of central Australia. We show that Lake Mega-Frome was connected for the last time to adjacent Lake Eyre at 50-47 ka, forming the largest remaining interconnected system of paleolakes on …
Alunite Formation Within Silica Stalactites From The Sydney Region, South-Eastern Australia, Robert A. Wray
Alunite Formation Within Silica Stalactites From The Sydney Region, South-Eastern Australia, Robert A. Wray
Faculty of Science - Papers (Archive)
"This paper presents X-ray diffraction and SEM evidence for the formation of alunite, and possibly small quantities of natroalunite, within opal-A stalactites formed on quartz sandstone near Sydney in south-eastern, Australia. Alunite has been reported as a speleogenetic mineral from sediments within a number of caves around the world, but this is believed to be the first report of speleothemic alunite in opaline silica speleothems. Individual alunite crystals have not been visually identified, but SEM X-ray element mapping suggests the alunite has formed amongst kaolinite clay. Sedimentary alunite and natroalunite formation is usually associated with the reaction of sulphuric acid …
Phylum Arthropoda, Subphylum Trilobitomorpha: Trilobites, Anthony J. Wright, Roger A. Cooper
Phylum Arthropoda, Subphylum Trilobitomorpha: Trilobites, Anthony J. Wright, Roger A. Cooper
Faculty of Science - Papers (Archive)
This volume is the second of three that provide a complete review and inventory of New Zealand's entire living and fossil biodiversity - an international effort involving more than 220 New Zealand and overseas specialists and the most comprehensive of its kind in the world. Together, the three volumes will list every one of the almost 55,000 known species of New Zealand's animals, plants, fungi and micro-organisms. Volume 2 mostly deals with the major branch of the animal kingdom known as Ecdysozoa (moulting animals), which includes arachnids, centipedes and millipedes, crustaceans and insects. It also includes the enigmatic phylum Chaetognatha …
Soils Of Low Elevation Coral Structures, John Morrison
Soils Of Low Elevation Coral Structures, John Morrison
Faculty of Science - Papers (Archive)
The small islands of the South Pacific region, like many other parts of the world, arc (~\I\j riencing population growth and, more particularly, the movement of people into )11,1I1!1 urban centres. Most Pacific cities, especially the capitals of regional countries, arc locili ",I in naturally protected coastal waterways. This is a historical situation, arising from III,' need to provide protected deep-water harbours for ships, the main form of internaliol\,d travel and trade. These waters are protected by offshore barrier reefs, by islands or by ril(,1 ine deltas. However, these protective mechanisms also have the effect of limiting mix!II): of near-shore …
Paleoclimate From Corals, Helen V. Mcgregor
Paleoclimate From Corals, Helen V. Mcgregor
Faculty of Science - Papers (Archive)
Ocean- atmosphere interactions in the tropics have farreaching conscqucnccs for climate variabi lity across the globe. The tropics drive heat transfer to the poles, and tropical inter-annual oscillations such as the El Nino-Southern Oscillation (ENSO) and Indian Ocean dipole (IOD), via atmospheric tcleconncctions, affcct rain rail patterns and climate conditions in arcas far bcyond the tropics (Ropelewski and Halpert, 1987), causing major socioeconomic impacts. Monitoring eIT0l1s have focused on improving obscrvations and undcrstanding of tropical climate variability, with the view to refining modeling or the tropical oceans and atmosphere. Despite these efforts, most instrumcntal records span only the past few …
Global Co(2) Fluxes Inferred From Surface Air-Sample Measurements And From Tccon Retrievals Of The Co(2) Total Column, Frederic Chevallier, Nicholas M. Deutscher, T J. Conway, P Ciais, L Ciattaglia, S Dohe, M Frohlich, A J. Gomez-Pelaez, David W. Griffith, F Hase, L Haszpra, Paul Krummel, E Kyro, C Labuschagne, R Lagenfelds, T Machidda, F Maignan, H Matsueda, I Morino, Justus Notholt, M Ramonet, Y Sawa, M Schmidt, V Sherlock, P Steele, K Strong, R Sussmann, Paul O. Wennberg, Steven C. Wofsy, D Worthy, Debra Wunch, M Zimnoch
Global Co(2) Fluxes Inferred From Surface Air-Sample Measurements And From Tccon Retrievals Of The Co(2) Total Column, Frederic Chevallier, Nicholas M. Deutscher, T J. Conway, P Ciais, L Ciattaglia, S Dohe, M Frohlich, A J. Gomez-Pelaez, David W. Griffith, F Hase, L Haszpra, Paul Krummel, E Kyro, C Labuschagne, R Lagenfelds, T Machidda, F Maignan, H Matsueda, I Morino, Justus Notholt, M Ramonet, Y Sawa, M Schmidt, V Sherlock, P Steele, K Strong, R Sussmann, Paul O. Wennberg, Steven C. Wofsy, D Worthy, Debra Wunch, M Zimnoch
Faculty of Science - Papers (Archive)
"We present the first estimate of the global distribution of CO(2) surface fluxes from 14 stations of the Total Carbon Column Observing Network (TCCON). The evaluation of this inversion is based on 1) comparison with the fluxes from a classical inversion of surface air-sample-measurements, and 2) comparison of CO(2) mixing ratios calculated from the inverted fluxes with independent aircraft measurements made during the two years analyzed here, 2009 and 2010. The former test shows similar seasonal cycles in the northern hemisphere and consistent regional carbon budgets between inversions from the two datasets, even though the TCCON inversion appears to be …
Chemically Activated Reactions On The C7h5 Energy Surface: Propargyl + Diacetylene, I-C5h3 + Acetylene, And N-C5h3 + Acetylene, Gabriel Da Silva, Adam J. Trevitt
Chemically Activated Reactions On The C7h5 Energy Surface: Propargyl + Diacetylene, I-C5h3 + Acetylene, And N-C5h3 + Acetylene, Gabriel Da Silva, Adam J. Trevitt
Faculty of Science - Papers (Archive)
This study uses computational chemistry and statistical reaction rate theory to investigate the chemically activated reaction of diacetylene (butadiyne, C4H2) with the propargyl radical (C •H2CCH) and the reaction of acetylene (C 2H2) with the i-C5H3 (CH 2CCCC•H) and n-C5H3 (CHCC •HCCH) radicals. A detailed G3SX-level C7H 5 energy surface demonstrates that the C3H3 + C4H2 and C5H3 + C2H 2 addition reactions proceed with moderate barriers, on the order of 10 to 15 kcal mol-1, and form activated open-chain C 7H5 species that can isomerize to the fulvenallenyl radical with the highest barrier still significantly below the entrance channel …
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Faculty of Science - Papers (Archive)
α-Carboxylate radical anions are potential reactive intermediates in the free radical oxidation of biological molecules (e.g., fatty acids, peptides and proteins). We have synthesised well-defined α-carboxylate radical anions in the gas phase by UV laser photolysis of halogenated precursors in an ion-trap mass spectrometer. Reactions of isolated acetate (CH2CO 2-) and 1-carboxylatobutyl (CH3CH 2CH2CHCO2-) radical anions with dioxygen yield carbonate (CO3-) radical anions and this chemistry is shown to be a hallmark of oxidation in simple and alkyl-substituted cross-conjugated species. Previous solution phase studies have shown that Cα-radicals in peptides, formed from free radical damage, combine with dioxygen to form …
Importance Of Secondary Sources In The Atmospheric Budgets Of Formic And Acetic Acids, Fabien Paulot, Debra Wunch, John D. Crounse, G C. Toon, Dylan B. Millet, Peter F. Decarlo, C Vigouroux, Nicholas M. Deutscher, G Gonzalez Abad, Justus Notholt, Thorsten Warneke, J Hannigan, Carsten Warneke, Joost A. De Gouw, Edward Dunlea, M De Maziere, David W. Griffith, P Bernath, J L. Jimenez, Paul O. Wennberg
Importance Of Secondary Sources In The Atmospheric Budgets Of Formic And Acetic Acids, Fabien Paulot, Debra Wunch, John D. Crounse, G C. Toon, Dylan B. Millet, Peter F. Decarlo, C Vigouroux, Nicholas M. Deutscher, G Gonzalez Abad, Justus Notholt, Thorsten Warneke, J Hannigan, Carsten Warneke, Joost A. De Gouw, Edward Dunlea, M De Maziere, David W. Griffith, P Bernath, J L. Jimenez, Paul O. Wennberg
Faculty of Science - Papers (Archive)
We present a detailed budget of formic and acetic acids, two of the most abundant trace gases in the atmosphere. Our bottom-up estimate of the global source of formic and acetic acids are ~1200 and ~1400 Gmol yr−1, dominated by photochemical oxidation of biogenic volatile organic compounds, in particular isoprene. Their sinks are dominated by wet and dry deposition. We use the GEOS-Chem chemical transport model to evaluate this budget against an extensive suite of measurements from ground, ship and satellite-based Fourier transform spectrometers, as well as from several aircraft campaigns over North America. The model captures the seasonality of …
Rotationally Resolved Infrared Spectrum Of The Na+-D2 Complex: An Experimental And Theoretical Study, Berwyck L. Poad, V Dryza, J Klos, A A. Buchachenko, E J. Bieske
Rotationally Resolved Infrared Spectrum Of The Na+-D2 Complex: An Experimental And Theoretical Study, Berwyck L. Poad, V Dryza, J Klos, A A. Buchachenko, E J. Bieske
Faculty of Science - Papers (Archive)
The infrared spectrum of mass-selected Na+-D2 complexes is recorded in the D-D stretch vibration region (2915-2972 cm−1) by detecting Na+ photofragments resulting from photo-excitation of the complexes. Analysis of the rotationally resolved spectrum confirms a T-shaped equilibrium geometry for the complex and a vibrationally averaged intermolecular bond length of 2.461 Å. The D-D stretch band centre occurs at 2944.04 cm−1, representing a −49.6 cm−1 shift from the Q1(0) transition of the free D2 molecule. Variational rovibrational energy level calculations are performed for Na+-D2 utilising an ab initio potential energy surface developed previously for investigating the Na+-H2 complex [B. L. J. …