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  • Copernicus Publications (EGU)  (2)
  • American Society of Limnology and Oceanography  (1)
  • Cham :Springer International Publishing AG,  (1)
  • 1
    Online Resource
    Online Resource
    Cham :Springer International Publishing AG,
    Keywords: Polarization (Nuclear physics). ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (414 pages)
    Edition: 2nd ed.
    ISBN: 9783319552163
    Series Statement: Springer Series on Atomic, Optical, and Plasma Physics Series ; v.96
    DDC: 539.757
    Language: English
    Note: Intro -- Foreword to the Second Edition -- Foreword to the First Edition -- Preface to the Second Edition -- Preface to the First Edition -- Acknowledgements -- Contents -- Notation -- Basic Concepts -- 1 Introduction -- 1.1 Motivation -- 1.2 Historical Perspective -- 1.3 Modern Approaches -- References -- 2 Polarized Light -- 2.1 Polarization of Coherent Electromagnetic Radiation -- 2.1.1 Maxwell's Theory of Electromagnetic Radiation -- 2.1.2 The Polarization Ellipse -- 2.1.3 Parameterization of Polarization: Stokes Vectors -- 2.1.4 The Principal Frame -- 2.1.5 The Poincaré Sphere -- 2.2 Electric Dipole Radiation from Atomic Transitions -- 2.2.1 Coordinate Frames, Scattering Amplitudes, and Stokes Parameters -- 2.2.2 Atomic State Parameters, Electron Charge Clouds, and Their Experimental Determination -- 2.2.3 The Incoherent Case with Conservation of Atomic Reflection Symmetry -- 2.2.4 The Incoherent Case Without Conservation of Atomic Reflection Symmetry -- 2.2.5 Summary of Parameterization for P-State Excitation -- 2.2.6 Extension to Coherently Excited Stark Manifolds -- References -- 3 Polarized Electrons -- 3.1 The Dirac Equation -- 3.2 Pure Spin States: State Vector Description -- 3.3 Mixed Spin States: Density Matrix Description -- 3.4 Experimental Determination of Electron Polarization -- References -- 4 Experimental Geometries and Approaches -- 4.1 Integrated Cross Sections and Alignment -- 4.1.1 Schematic Setup for Angle-Integrated Measurements -- 4.1.2 Setups with Results for Electron Impact and Atom Impact Excitation -- 4.2 Differential Cross Sections -- 4.2.1 Schematic Setups for Angle-Differential Measurements -- 4.2.2 A Setup with Results for Electron--Atom Collisions -- 4.2.3 The Magnetic Angle Changer -- 4.2.4 Setups with Results for Electron Impact Ionization -- 4.2.5 A Setup with Results for Atom Impact Excitation. , 4.3 Planar Scattering Symmetry: Alignment and Orientation Parameters -- 4.3.1 Schematic Setups for Coherence and Correlation Analysis -- 4.3.2 Setups with Results for Electron Impact Excitation and De-excitation -- 4.3.3 Setups with Results for Atom Impact Excitation -- 4.4 Generalized STU Parameters for Electron Collisions -- 4.5 Generalized Stokes Parameters for Electron--Atom Collisions -- 4.6 Atom--Atom Collisions with Laser-Prepared Targets -- References -- 5 Density Matrices: Connection Between Experiment and Theory -- 5.1 Motivation -- 5.2 Scattering Amplitudes -- 5.2.1 Scattering Amplitudes in Different Coordinate Frames -- 5.2.2 Symmetry Properties -- 5.2.3 Scattering Amplitudes in the Non-relativistic Limit -- 5.3 Density Matrices -- 5.4 An Explicit Example: Generalized STU Parameters -- 5.4.1 Definition in Terms of Scattering Amplitudes -- 5.4.2 Exact Symmetry Relationships -- 5.4.3 An Approximate Symmetry: The Fine-Structure Effect -- 5.5 Irreducible Tensor Operators and State Multipoles -- 5.5.1 Basic Definitions -- 5.5.2 Coupled Systems -- 5.5.3 Time Evolution of State Multipoles: Quantum Beats -- 5.5.4 Time Integration over Quantum Beats -- 5.6 Stokes Parameters -- 5.7 Atomic and Photon Density Matrices for P-State Excitation -- References -- 6 Computational Methods -- 6.1 Electron Versus Heavy-Particle Impact -- 6.2 Computational Methods for Electron Scattering -- 6.2.1 Potential Scattering -- 6.2.2 Perturbation Approaches -- 6.2.3 The Close-Coupling Expansion -- 6.2.4 Time-Dependent Approaches -- 6.2.5 Recent Developments -- 6.3 Computational Methods for Heavy-Particle Collisions -- 6.3.1 Semi-classical Approaches -- 6.3.2 Classical-Trajectory Monte-Carlo Approach -- 6.4 Visualization of Charge Clouds -- References -- Case Studies -- 7 Electron Impact Excitation -- 7.1 Angle-Integrated Stokes Parameters and Cross Sections. , 7.1.1 Excitation of the (6s6p) States in Hg -- 7.1.2 Excitation of Ions: Cd+(2P3/2) -- 7.1.3 An Unresolved Mystery: Electron Impact Excitation of (4s5s)3S1 in Zn and (6s7s)3S1 in Hg -- 7.2 Angle-Differential Stokes and STU Parameters -- 7.2.1 Electron Impact Excitation of Helium -- 7.2.2 Electron Impact Excitation of Hydrogen, Lithium, and Sodium -- 7.2.3 Electron Impact Excitation of Heavy Noble Gases -- 7.2.4 Electron Impact Excitation of Mercury -- 7.2.5 Elastic Electron Scattering from Cesium -- 7.2.6 Recent Developments in Electron Scattering from Cesium -- 7.3 Conclusions -- References -- 8 Ion and Atom Impact Excitation -- 8.1 Angle-Differential S rightarrow P, D Excitation and Transfer -- 8.1.1 S rightarrow P, D Excitation in Mg+- and Li-Rare-Gas Systems -- 8.1.2 S rightarrow P Transfer Excitation in B3+-He, Ne Collisions -- 8.1.3 S rightarrow P Transfer in Small-Angle H+, Li+-Na(3s) Collisions -- 8.1.4 Vortex Formation in Antiproton-Atomic-Hydrogen Collisions -- 8.2 Angle-Integrated Alignment Studies Using Optically Prepared Targets -- 8.2.1 Alignment Effects in H+, Li+-Na(3p) Collisions -- 8.2.2 Alignment Effects in He2+-Na(3p) Collisions -- 8.3 Angle-Differential Studies Using Optically Prepared Targets -- 8.3.1 Level Populations in H+-Na(3p)rightarrowH(n=2,3)-Na+ Scattering -- 8.3.2 Level Populations in Li+-Na(3p)rightarrowLi(2p)-Na+ Scattering -- 8.3.3 Level Populations in He+ - Na(3p)rightarrowHe(2p)-Na+ Scattering -- 8.4 Angle-Differential Studies Using Optically Prepared -- 8.4.1 H+-Na(3p)rightarrowH (2p)-Na+ Scattering Experiments -- 8.4.2 Li+-Na(3p)rightarrowLi(2p)--Na+ Scattering Experiments -- 8.5 Reaction Microscope Studies: COLTRIMS with Alkali MOTs -- 8.5.1 Li+ Capture from a Na (3s, 3p) MOT -- 8.5.2 Na+ Capture from a Rb (5p) MOT -- References -- 9 Propensity Rules. , 9.1 Orientation for S to P Impact Excitation by Electrons and Positrons -- 9.2 Orientation for S to P Impact Excitation by Protons and Antiprotons -- 9.3 Orientation for Excitation and De-Excitation by Electrons and Positrons -- 9.4 Principal Quantum Number Dependence of Orientation and Alignment Parameters -- 9.5 Spin-Dependent Propensities -- 9.6 Validity Limits of Propensity Rules -- 9.6.1 Electron Impact Excitation of Neon -- 9.6.2 Electron Impact Excitation of He(1s3d)1D -- References -- 10 Impact Ionization -- 10.1 Ionization by Electron Impact -- 10.1.1 Angle-Integrated Studies -- 10.1.2 Angle-Differential Studies -- 10.1.3 Selected Developments Since 2001 -- 10.2 Ionization by Heavy-Particle Impact: Reaction Microscope Studies with Optically Prepared Targets -- 10.3 Ionization with Excitation by Heavy-Particle Impact -- 10.3.1 Angle-Integrated Studies -- 10.3.2 Angle-Differential Studies -- References -- 11 Photo-Driven Processes -- 11.1 Introductory Remarks -- 11.2 Photoionization by Continuous Radiation -- 11.3 Photoionization by Short-Pulse Radiation -- References -- 12 Related Topics and Applications -- 12.1 Spin-Polarized Auger Electrons -- 12.2 Autoionization Anisotropies in Heavy-Particle Collisions -- 12.3 Collisions with Molecules -- 12.3.1 Electron Collisions with Molecules -- 12.3.2 Heavy-Particle Collisions with Molecules -- 12.4 Collisions with Surfaces and Foils -- 12.5 Polarization in Collisional Broadening and Redistribution -- 12.6 Alignment and Orientation Studies at Thermal Energies -- 12.6.1 Alignment Studies Involving an Optically Prepared Atom -- 12.6.2 Alignment and Orientation Studies Involving Two Optically Prepared Atoms -- 12.7 Plasma Polarization Spectroscopy -- 12.8 Spin-Polarized Beams for Nuclear and Particle Physics -- 12.9 Quantum Entanglement and Bell Correlation in Electron-Exchange Collisions. , References -- Selection of Historical Papers (1925-1976) -- 13 Introductory Summaries -- Appendix Further Readings -- Index.
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  • 2
    Publication Date: 2019-09-23
    Description: The role of the global surface ocean as a source and sink for atmospheric carbon dioxide and the flux strengths between the ocean and the atmosphere can be quantified by measuring the fugacity of CO2 (ƒCO2) as well as the dissolved inorganic carbon (DIC) concentration and its isotopic composition in surface seawater. In this work, the potential of continuous wave cavity ringdown spectroscopy (cw-CRDS) for autonomous underway measurements of ƒCO2 and the stable carbon isotope ratio of DIC [δ13C(DIC)] is explored. For the first time, by using a conventional air-sea equilibrator setup, both quantities were continuously and simultaneously recorded during a field deployment on two research cruises following meridional transects across the Atlantic Ocean (Bremerhaven, Germany–Punta Arenas, Chile). Data are compared against reference measurements by an established underway CO2 monitoring system and isotope ratio mass spectrometric analysis of individual water samples. Agreement within ΔƒCO2 = 0.35 μatm for atmospheric and ΔƒCO2 = 2.5 μatm and Δδ13C(DIC) =0.33‰ for seawater measurements have been achieved. Whereas “calibration-free” ƒCO2 monitoring is feasible, the measurement of accurate isotope ratios relies on running reference standards on a daily basis. Overall, the installed CRDS/equilibrator system was shown to be capable of reliable online monitoring of ƒCO2, equilibrium δ13C(CO2), δ13C(DIC), and pO2 aboard moving research vessels, thus making possible corresponding measurements with high spatial and temporal resolution.
    Type: Article , PeerReviewed
    Format: text
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  • 3
    Publication Date: 2021-04-21
    Description: The stable carbon isotope composition of dissolved inorganic carbon (δ13C-DIC) can be used to quantify fluxes within the carbon system. For example, knowing the δ13C signature of the inorganic carbon pool can help in describing the amount of anthropogenic carbon in the water column. The measurements can also be used for evaluating modeled carbon fluxes, for making basin-wide estimates of anthropogenic carbon, and for studying seasonal and interannual variability or decadal trends in interior ocean biogeochemistry. For all these purposes, it is not only important to have a sufficient amount of data, but these data must also be internally consistent and of high quality. In this study, we present a δ13C-DIC dataset for the North Atlantic which has undergone secondary quality control. The data originate from oceanographic research cruises between 1981 and 2014. During a primary quality control step based on simple range tests, obviously bad data were flagged. In a second quality control step, biases between measurements from different cruises were quantified through a crossover analysis using nearby data of the respective cruises, and values of biased cruises were adjusted in the data product. The crossover analysis was possible for 24 of the 32 cruises in our dataset, and adjustments were applied to 11 cruises. The internal accuracy of this dataset is 0.017 ‰.
    Type: Article , PeerReviewed
    Format: text
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  • 4
    Publication Date: 2023-02-08
    Description: The Labrador Sea is important for the modern global thermohaline circulation system through the formation of intermediate Labrador Sea Water (LSW) that has been hypothesized to stabilize the modern mode of North Atlantic deep-water circulation. The rate of LSW formation is controlled by the amount of winter heat loss to the atmosphere, the expanse of freshwater in the convection region and the inflow of saline waters from the Atlantic. The Labrador Sea, today, receives freshwater through the East and West Greenland currents (EGC, WGC) and the Labrador Current (LC). Several studies have suggested the WGC to be the main supplier of freshwater to the Labrador Sea, but the role of the southward flowing LC in Labrador Sea convection is still debated. At the same time, many paleoceanographic reconstructions from the Labrador Shelf focussed on late deglacial to early Holocene meltwater run-off from the Laurentide Ice Sheet (LIS), whereas little information exists about LC variability since the final melting of the LIS about 7000 years ago. In order to enable better assessment of the role of the LC in deep-water formation and its importance for Holocene climate variability in Atlantic Canada, this study presents high-resolution middle to late Holocene records of sea surface and bottom water temperatures, freshening, and sea ice cover on the Labrador Shelf during the last 6000 years. Our records reveal that the LC underwent three major oceanographic phases from the mid- to late Holocene. From 6.2 to 5.6 ka, the LC experienced a cold episode that was followed by warmer conditions between 5.6 and 2.1 ka, possibly associated with the late Holocene thermal maximum. While surface waters on the Labrador Shelf cooled gradually after 3 ka in response to the neoglaciation, Labrador Shelf subsurface or bottom waters show a shift to warmer temperatures after 2.1 ka. Although such an inverse stratification by cooling of surface and warming of subsurface waters on the Labrador Shelf would suggest a diminished convection during the last 2 millennia compared to the mid-Holocene, it remains difficult to assess whether hydrographic conditions in the LC have had a significant impact on Labrador Sea deep-water formation.
    Type: Article , PeerReviewed
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