Browsing by Author "Tennyson, Jonathan"

Now showing 1 - 5 of 5
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    Foundations of plasma standards
    (Bristol : IOP Publ., 2023) Alves, Luís L.; Becker, Markus M.; van Dijk, Jan; Gans, Timo; Go, David B.; Stapelmann, Katharina; Tennyson, Jonathan; Turner, Miles M.; Kushner, Mark J.
    The field of low-temperature plasmas (LTPs) excels by virtue of its broad intellectual diversity, interdisciplinarity and range of applications. This great diversity also challenges researchers in communicating the outcomes of their investigations, as common practices and expectations for reporting vary widely in the many disciplines that either fall under the LTP umbrella or interact closely with LTP topics. These challenges encompass comparing measurements made in different laboratories, exchanging and sharing computer models, enabling reproducibility in experiments and computations using traceable and transparent methods and data, establishing metrics for reliability, and in translating fundamental findings to practice. In this paper, we address these challenges from the perspective of LTP standards for measurements, diagnostics, computations, reporting and plasma sources. This discussion on standards, or recommended best practices, and in some cases suggestions for standards or best practices, has the goal of improving communication, reproducibility and transparency within the LTP field and fields allied with LTPs. This discussion also acknowledges that standards and best practices, either recommended or at some point enforced, are ultimately a matter of judgment. These standards and recommended practices should not limit innovation nor prevent research breakthroughs from having real-time impact. Ultimately, the goal of our research community is to advance the entire LTP field and the many applications it touches through a shared set of expectations.
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    LXCat: an Open-Access, Web-Based Platform for Data Needed for Modeling Low Temperature Plasmas
    (Weinheim : Wiley-VCH, 2016) Pitchford, Leanne C.; Alves, Luis L.; Bartschat, Klaus; Biagi, Stephen F.; Bordage, Marie‐Claude; Bray, Igor; Brion, Chris E.; Brunger, Michael J.; Campbell, Laurence; Chachereau, Alise; Chaudhury, Bhaskar; Christophorou, Loucas G.; Carbone, Emile; Dyatko, Nikolay A.; Franck, Christian M.; Fursa, Dmitry V.; Gangwar, Reetesh K.; Guerra, Vasco; Haefliger, Pascal; Hagelaar, Gerjan J. M.; Hoesl, Andreas; Itikawa, Yukikazu; Kochetov, Igor V.; McEachran, Robert P.; Morgan, W. Lowell; Napartovich, Anatoly P.; Puech, Vincent; Rabie, Mohamed; Sharma, Lalita; Srivastava, Rajesh; Stauffer, Allan D.; Tennyson, Jonathan; de Urquijo, Jaime; van Dijk, Jan; Viehland, Larry A.; Zammit, Mark C.; Zatsarinny, Oleg; Pancheshnyi, Sergey
    LXCat is an open-access platform (www.lxcat.net) for curating data needed for modeling the electron and ion components of technological plasmas. The data types presently supported on LXCat are scattering cross sections and swarm/transport parameters, ion-neutral interaction potentials, and optical oscillator strengths. Twenty-four databases contributed by different groups around the world can be accessed on LXCat. New contributors are welcome; the database contributors retain ownership and are responsible for the contents and maintenance of the individual databases. This article summarizes the present status of the project.
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    QDB: A new database of plasma chemistries and reactions
    (Bristol : IOP Publ., 2017) Tennyson, Jonathan; Rahimi, Sara; Hill, Christian; Tse, Lisa; Vibhakar, Anuradha; Akello-Egwel, Dolica; Brown, Daniel B.; Dzarasova, Anna; Hamilton, James R.; Jaksch, Dagmar; Mohr, Sebastian; Wren-Little, Keir; Bruckmeier, Johannes; Agarwal, Ankur; Bartschat, Klaus; Bogaerts, Annemie; Booth, Jean-Paul; Goeckner, Matthew J.; Hassouni, Khaled; Itikawa, Yukikazu; Braams, Bastiaan J; Krishnakumar, E.; Laricchiuta, Annarita; Mason, Nigel J.; Pandey, Sumeet; Petrovic, Zoran Lj.; Pu, Yi-Kang; Ranjan, Alok; Rauf, Shahid; Schulze, Julian; Turner, Miles M.; Ventzek, Peter; Whitehead, J. Christopher; Yoon, Jung-Sik
    One of the most challenging and recurring problems when modeling plasmas is the lack of data on the key atomic and molecular reactions that drive plasma processes. Even when there are data for some reactions, complete and validated datasets of chemistries are rarely available. This hinders research on plasma processes and curbs development of industrial applications. The QDB project aims to address this problem by providing a platform for provision, exchange, and validation of chemistry datasets. A new data model developed for QDB is presented. QDB collates published data on both electron scattering and heavy-particle reactions. These data are formed into reaction sets, which are then validated against experimental data where possible. This process produces both complete chemistry sets and identifies key reactions that are currently unreported in the literature. Gaps in the datasets can be filled using established theoretical methods. Initial validated chemistry sets for SF6/CF4/O2 and SF6/CF4/N2/H2 are presented as examples.
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    R-matrix calculations of electron impact electronic excitation of BeH
    (Bristol : IOP Publ., 2017-08-08) Darby-Lewis, Daniel; Mašín, Zdeněk; Tennyson, Jonathan
    The R-matrix method is used to perform high-level calculations of electron collisions with beryllium mono-hydride at its equilibrium geometry with a particular emphasis on electron impact electronic excitation. Several target and scattering models are considered. The calculations were performed using (1) the UKRMol suite which relies on the use of Gaussian type orbitals (GTOs) to represent the continuum and (2) using the new UKRMol+ suite which allows the inclusion of B-spline type orbitals in the basis for the continuum. The final close-coupling scattering models used the UKRMol+ code and a frozen core, valence full configuration interaction, method based on a diffuse GTO atomic basis set. The calculated electronic properties of the molecule are in very good agreement with state-of-the-art electronic structure calculations. The use of the UKRMol+ suite proved critical since it allowed the use of a large R-matrix sphere (35 Bohr), necessary to contain the diffuse electronic states of the molecule. The corresponding calculations using UKRMol are not possible due to numerical problems associated with the combination of GTO-only continuum and a large R-matrix sphere. This work provides the first demonstration of the utility and numerical stability of the new UKRMol+ code. The inelastic cross sections obtained here present a significant improvement over the results of earlier studies on BeH.
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    Recent developments in R-matrix applications to molecular processes
    (Bristol : IOP Publ., 2015) Mašín, Zdeněk; Harvey, Alex; Houfek, Karel; Brambila, Danilo S.; Morales, Felipe; Gorfinkiel, Jimena D.; Tennyson, Jonathan; Smirnova, Olga
    We report on recent developments of the UKRmol suite, an implementation of the molecular R- matrix method and present examples of the calculations (e.g. electron scattering, photoionization, high harmonic generation, etc.) it has enabled.