Download or read book Oxygen Isotope Fractionation in the Vacuum Ultraviolet Photodissociation of Carbon Monoxide written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Several absorption bands exist in the VUV region of Carbon monoxide (CO). Emission spectra indicate that these bands are all predissociative. An experimental investigation of CO photodissociation by vacuum ultraviolet photons (90 to 108 nm; 1̃3 to 11 eV) from the Advanced Light Source Synchrotron and direct measurement of the associated oxygen isotopic composition of the products are presented here. A wavelength dependency of the oxygen isotopic composition in the photodissociation product was observed. Slope values (?'18O/?'17O) ranging from 0.76 to 1.32 were observed in oxygen three-isotope space (?'18O vs.?'17O) which correlated with increasing synchrotron photon energy, and indicate a dependency of the upper electronic state specific dissociation dynamics (e.g., perturbation and coupling associated with a particular state). An unprecedented magnitude in isotope separation was observed for photodissociation at the 105 and 107 nm synchrotron bands and are found to be associated with accidental predissociation of the vibrational states (? = 0 and 1) of the upper electronic state E1?. For each synchrotron band, a large (few hundred per mil) extent of isotopic fractionation was observed and the range of fractionation is a combination of column density and exposure time. A significant temperature dependency in oxygen isotopic fractionation was observed, indicating a rotational level dependency in the predissociation process.
Download or read book Triple Oxygen Isotope Geochemistry written by Ilya N. Bindeman and published by Walter de Gruyter GmbH & Co KG. This book was released on 2021-02-22 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 86 of Reviews in Mineralogy and Geochemistry concentrates on understanding the variations among ratios of the three isotopes of oxygen, with primary emphasis on terrestrial systems. Triple oxygen isotope variations may be related to large, mass-independent fractionation effects such observed in the Earth atmosphere or may be small and related to minute variations due to purely mass-dependent processes. Recent advancements in analytical resolution now allow for the identification of processes and distinct reservoirs that were formerly hidden in the paradigm of a "single terrestrial fractionation line". New, high-resolution measurements are accompanied by advances in theoretical calculations that dovetail with empirical calibrations and applications throughout this volume. 14 chapters span a wide range of subjects: from ab-initio theoretical approaches to observation of triple oxygen isotope variations in the Earth litho-, hydro- and atmosphere.
Download or read book Treatise on Geochemistry written by and published by Newnes. This book was released on 2013-10-19 with total page 14787 pages. Available in PDF, EPUB and Kindle. Book excerpt: This extensively updated new edition of the widely acclaimed Treatise on Geochemistry has increased its coverage beyond the wide range of geochemical subject areas in the first edition, with five new volumes which include: the history of the atmosphere, geochemistry of mineral deposits, archaeology and anthropology, organic geochemistry and analytical geochemistry. In addition, the original Volume 1 on "Meteorites, Comets, and Planets" was expanded into two separate volumes dealing with meteorites and planets, respectively. These additions increased the number of volumes in the Treatise from 9 to 15 with the index/appendices volume remaining as the last volume (Volume 16). Each of the original volumes was scrutinized by the appropriate volume editors, with respect to necessary revisions as well as additions and deletions. As a result, 27% were republished without major changes, 66% were revised and 126 new chapters were added. In a many-faceted field such as Geochemistry, explaining and understanding how one sub-field relates to another is key. Instructors will find the complete overviews with extensive cross-referencing useful additions to their course packs and students will benefit from the contextual organization of the subject matter Six new volumes added and 66% updated from 1st edition. The Editors of this work have taken every measure to include the many suggestions received from readers and ensure comprehensiveness of coverage and added value in this 2nd edition The esteemed Board of Volume Editors and Editors-in-Chief worked cohesively to ensure a uniform and consistent approach to the content, which is an amazing accomplishment for a 15-volume work (16 volumes including index volume)!
Download or read book Multiple Stable Oxygen Isotope Analysis of Atmospheric Carbon Monoxide and Its Sources written by Amy Kathleen Huff and published by . This book was released on 1998 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Encyclopedia of Astrobiology written by Muriel Gargaud and published by Springer Nature. This book was released on 2023-07-27 with total page 3376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Now in its third edition the Encyclopedia of Astrobiology serves as the key to a common understanding in the extremely interdisciplinary community of astrobiologists. Each new or experienced researcher and graduate student in adjacent fields of astrobiology will appreciate this reference work in the quest to understand the big picture. The carefully selected group of active researchers contributing to this work are aiming to give a comprehensive international perspective on and to accelerate the interdisciplinary advance of astrobiology. The interdisciplinary field of astrobiology constitutes a joint arena where provocative discoveries are coalescing concerning, e.g. the prevalence of exoplanets, the diversity and hardiness of life, and its chances for emergence. Biologists, astrophysicists, (bio)-chemists, geoscientists and space scientists share this exciting mission of revealing the origin and commonality of life in the Universe. With its overview articles and its definitions the Encyclopedia of Astrobiology not only provides a common language and understanding for the members of the different disciplines but also serves for educating a new generation of young astrobiologists who are no longer separated by the jargon of individual scientific disciplines. This new edition offers ~170 new entries. More than half of the existing entries were updated, expanded or supplemented with figures supporting the understanding of the text. Especially in the fields of astrochemistry and terrestrial extremophiles but also in exoplanets and space sciences in general there is a huge body of new results that have been taken into account in this new edition. Because the entries in the Encyclopedia are in alphabetical order without regard for scientific field, this edition includes a section “Astrobiology by Discipline” which lists the entries by scientific field and subfield. This should be particularly helpful to those enquiring about astrobiology, as it illustrates the broad and detailed nature of the field.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976-03 with total page 938 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Production and Characterisation of High Purity Ozone and Experimental and Modelling Studies of Anomalous Oxygen Isotope Effects in the Formation of Carbon Dioxide from Irradiated Mixtures of Carbon Monoxide and Ozone Or Oxygen written by Daniela Simone and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ozone formation reaction O+O2+M→O3+M is a unique example of a chemical reaction that leads to an anomalous isotopic composition of the products, most likely due to symmetry - breaking effects. So far, results on other chemical systems that might show similar effects are spurious, even though such claims concerning reactions other than the formation of ozone have been made repeatedly.This applies in particular to the spin forbidden O+CO+M→CO2+M reaction, where two studies report a mass-independent fractionation of about 8%. Nevertheless, the presence of ozone in these experiments raises questions as to the validity of this assertion. We thus make a new attempt to study the O+CO+M reaction in the photoreactor at CCAR (University of Copenhagen) where reagents and contaminants are monitored on-line by FTIR spectroscopy. This study combined with the analysis of the spectral distribution of the employed lamps and isotope kinetic modeling lead to a complete re-interpretation of previous experiments. We conclude that available measurements are more compatible with the hypothesis that there is no mass-independent isotope fractionation in the O+CO reaction. We propose that all observations can be completely explained by an isotope transfer from ozone, involving photolytic production of O(1D) that in turn leads to OH radicals, which then rapidly form CO2 from reaction with CO. We also present a method to produce pure ozone samples and derive an upper limit on nitrogen oxide contaminations based on mass spectrometer measurements. These values will serve as benchmarks values for future studies of ozone absorption cross sections in the IR and UV.
Download or read book Experimental Study of Oxygen Isotopic Fractionation in the Oxidation of Silicon Monoxide written by Qingwei Dong and published by . This book was released on 1993 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Science written by John Michels (Journalist) and published by . This book was released on 2008 with total page 886 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography of Mass Spectroscopy Literature for 1971 written by and published by . This book was released on 1973 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photosynthetic Isotope Fractionation written by Glen Edward Martin and published by . This book was released on 1982 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Isotope Separation by Selective Photodissociation of Glyoxal written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissociation products, mainly formaldehyde and carbon monoxide, enriched in a desired isotope of carbon, oxygen, or hydrogen are obtained by the selective photodissociation of glyoxal wherein glyoxal is subjected to electromagnetic radiation of a predetermined wavelength such that photon absorption excites and induces dissociation of only those molecules of glyoxal containing the desired isotope.
Download or read book Physics Briefs written by and published by . This book was released on 1981-07 with total page 1542 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1984 with total page 924 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index Mathematics statistics Physics A E written by and published by . This book was released on 1984 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1989 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
