Author
Christian Hill
Other affiliations: International Atomic Energy Agency, Harvard University, University of Oxford
Bio: Christian Hill is an academic researcher from University College London. The author has contributed to research in topics: HITRAN & Spectral line. The author has an hindex of 26, co-authored 53 publications receiving 9465 citations. Previous affiliations of Christian Hill include International Atomic Energy Agency & Harvard University.
Topics: HITRAN, Spectral line, Absorption spectroscopy, Exoplanet, Ab initio
Papers published on a yearly basis
Papers
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Harvard University1, University of Reims Champagne-Ardenne2, College of William & Mary3, Old Dominion University4, University of Lisbon5, University of Burgundy6, California Institute of Technology7, Centre national de la recherche scientifique8, Université catholique de Louvain9, University of York10, University College London11, National Institute of Standards and Technology12, University of Waterloo13, National Center for Atmospheric Research14, University of Cologne15, Karlsruhe Institute of Technology16, Langley Research Center17
TL;DR: The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity, and molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth.
Abstract: This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided.
7,638 citations
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TL;DR: The ExoMol database as mentioned in this paper provides extensive line lists of molecular transitions which are valid over extended temperature ranges, including lifetimes of individual states, temperature-dependent cooling functions, Lande g-factors, partition functions, cross sections, k-coefficients and transition dipoles with phase relations.
421 citations
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University of Paris1, Université Paris-Saclay2, Pierre-and-Marie-Curie University3, University of Reims Champagne-Ardenne4, College of William & Mary5, Centre national de la recherche scientifique6, California Institute of Technology7, University of Grenoble8, University of Paris-Sud9, University College London10, Université catholique de Louvain11, university of lille12, University of Massachusetts Lowell13, University of Leicester14, University of Science and Technology of China15, University of Castilla–La Mancha16, Russian Academy of Sciences17, University of Colorado Boulder18, Tomsk Polytechnic University19, University of Cologne20, University of Oslo21, Karlsruhe Institute of Technology22, University of Lethbridge23, University College Cork24, Université libre de Bruxelles25
TL;DR: The GEISA database (Gestion et Etude des Informations Spectroscopiques Atmospheriques: Management and Study of Atmospheric Spectroscopic Information) has been developed and maintained by the ARA/ABC(t) group at LMD since 1974.
347 citations
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TL;DR: HAPI is a free Python library, which extends the capabilities of the HITRANonline interface and can be used to filter and process the structured spectroscopic data and incorporates a set of tools for spectra simulation accounting for the temperature, pressure, optical path length, and instrument properties.
Abstract: The HITRAN Application Programming Interface (HAPI) is presented. HAPI is a free Python library, which extends the capabilities of the HITRANonline interface ( www.hitran.org ) and can be used to filter and process the structured spectroscopic data. HAPI incorporates a set of tools for spectra simulation accounting for the temperature, pressure, optical path length, and instrument properties. HAPI is aimed to facilitate the spectroscopic data analysis and the spectra simulation based on the line-by-line data, such as from the HITRAN database [JQSRT (2013) 130, 4–50], allowing the usage of the non-Voigt line profile parameters, custom temperature and pressure dependences, and partition sums. The HAPI functions allow the user to control the spectra simulation and data filtering process via a set of the function parameters. HAPI can be obtained at its homepage www.hitran.org/hapi .
262 citations
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TL;DR: In this paper, a revised rotation-vibration line list for the combined hydrogen cyanide (HCN)/ hydrogen isocyanide (HNC) system is presented.
Abstract: A revised rotation-vibration line list for the combined hydrogen cyanide (HCN)/ hydrogen isocyanide (HNC) system is presented. The line list uses ab initio transi-tion intensities calculated previously (Harris et al., ApJ, 2002, 578, 657) and extensivedatasets of recently measured experimental energy levels (Mellau, J. Chem. Phys. andJ. Mol. Spectrosc. 2010-2011). The resulting line list has signi cantly more accuratewavelengths than previous ones for these systems. An improved value for the sepa-ration between HCN and HNC is adopted leading to an approximately 25 % lowerpredicted thermal population of HNC as a function of temperature in the key 2000 to3000 K region. Temperature-dependent partition functions and equilibrium constantsare presented. The line lists are validated by comparison with laboratory spectra andare presented in full as supplementary data to the article and at www.exomol.com.Key words: molecular data; opacity; astronomical data bases: miscellaneous; planetsand satellites: atmospheres; stars: low-mass
195 citations
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28,685 citations
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TL;DR: In this paper, a new molecular spectroscopic database for high-temperature modeling of the spectra of molecules in the gas phase is described, called HITEMP, which is analogous to the HITRAN database but encompasses many more bands and transitions than HitRAN for the absorbers H2O, CO2, CO, NO and OH.
Abstract: A new molecular spectroscopic database for high-temperature modeling of the spectra of molecules in the gas phase is described. This database, called HITEMP, is analogous to the HITRAN database but encompasses many more bands and transitions than HITRAN for the absorbers H2O, CO2, CO, NO, and OH. HITEMP provides users with a powerful tool for a great many applications: astrophysics, planetary and stellar atmospheres, industrial processes, surveillance, non-local thermodynamic equilibrium problems, and investigating molecular interactions, to name a few. The sources and implementation of the spectroscopic parameters incorporated into HITEMP are discussed.
1,715 citations
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TL;DR: This paper presented an up-to-date, comprehensive tabulation of EF for known pyrogenic species based on measurements made in smoke that has cooled to ambient temperature, but not yet undergone significant photochemical processing.
Abstract: . Biomass burning (BB) is the second largest source of trace gases and the largest source of primary fine carbonaceous particles in the global troposphere. Many recent BB studies have provided new emission factor (EF) measurements. This is especially true for non-methane organic compounds (NMOC), which influence secondary organic aerosol (SOA) and ozone formation. New EF should improve regional to global BB emissions estimates and therefore, the input for atmospheric models. In this work we present an up-to-date, comprehensive tabulation of EF for known pyrogenic species based on measurements made in smoke that has cooled to ambient temperature, but not yet undergone significant photochemical processing. All EFs are converted to one standard form (g compound emitted per kg dry biomass burned) using the carbon mass balance method and they are categorized into 14 fuel or vegetation types. Biomass burning terminology is defined to promote consistency. We compile a large number of measurements of biomass consumption per unit area for important fire types and summarize several recent estimates of global biomass consumption by the major types of biomass burning. Post emission processes are discussed to provide a context for the emission factor concept within overall atmospheric chemistry and also highlight the potential for rapid changes relative to the scale of some models or remote sensing products. Recent work shows that individual biomass fires emit significantly more gas-phase NMOC than previously thought and that including additional NMOC can improve photochemical model performance. A detailed global estimate suggests that BB emits at least 400 Tg yr−1 of gas-phase NMOC, which is almost 3 times larger than most previous estimates. Selected recent results (e.g. measurements of HONO and the BB tracers HCN and CH3CN) are highlighted and key areas requiring future research are briefly discussed.
1,472 citations
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TL;DR: In this article, the authors present the basis for each technique, recent developments in methods and performance limitations, and present a performance comparison of different techniques, taking data reported over the preceding decade, and draw conclusions from this benchmarking.
Abstract: The detection and measurement of gas concentrations using the characteristic optical absorption of the gas species is important for both understanding and monitoring a variety of phenomena from industrial processes to environmental change. This study reviews the field, covering several individual gas detection techniques including non-dispersive infrared, spectrophotometry, tunable diode laser spectroscopy and photoacoustic spectroscopy. We present the basis for each technique, recent developments in methods and performance limitations. The technology available to support this field, in terms of key components such as light sources and gas cells, has advanced rapidly in recent years and we discuss these new developments. Finally, we present a performance comparison of different techniques, taking data reported over the preceding decade, and draw conclusions from this benchmarking.
1,293 citations
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TL;DR: An in-depth view of Terahertz Band (0.1-10 THz) communication, which is envisioned as a key technology to satisfy the increasing demand for higher speed wireless communication, is provided.
1,206 citations