Browsing by Author "Lynas-Gray, Anthony E."

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    Exomol line lists – xliv. Infrared and ultraviolet line list for silicon monoxide (28si16o)
    (Oxford University Press, 2022) Yurchenko, Sergei N.; Tennyson, Jonathan; Lynas-Gray, Anthony E.
    A new silicon monoxide ( 28Si16O) line list covering infrared, visible, and ultraviolet regions called SiOUVenIR is presented. This line list extends the infrared EBJT ExoMol line list by including vibronic transitions to the A 1 and E 1+ electronic states. Strong perturbations to the A 1 band system are accurately modelled through the treatment of six dark electronic states: C 1−, D 1 , a 3+, b 3, e 3−, and d 3 . Along with the X 1+ ground state, these nine electronic states were used to build a comprehensive spectroscopic model of SiO using a combination of empirical and ab initio curves, including the potential energy (PE), spin–orbit, electronic angular momentum, and (transition) dipole moment curves. The ab initio PE and coupling curves, computed at the multireference configuration interaction level of theory, were refined by fitting their analytical representations to 2617 experimentally derived SiO energy levels determined from 97 vibronic bands belonging to the X–X, E–X, and A–X electronic systems through the MARVEL (Measured Active Rotational–Vibrational Energy Levels) procedure. 112 observed forbidden transitions from the C–X, D–X, e–X, and d–X bands were assigned using our predictions, and these could be fed back into the MARVEL procedure. The SiOUVenIR line list was computed using published ab initio transition dipole moments for the E–X and A–X bands; the line list is suitable for temperatures up to 10 000 K and for wavelengths longer than 140 nm. SiOUVenIR is available from www.exomol.com and the CDS data base.
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    Werner Eissner (1930–2022): a pioneer in computational atomic physics
    (Atoms, 2023) Lynas-Gray, Anthony E.; Bhatia, Anand K.; Mendoza, Claudio; Nahar, Sultana
    Werner Eissner (Figure 1), a pioneer in computational atomic physics, was born on 16 October 1930 in the city of Görlitz, Germany, to Bernhard and Frieda (née Eckert) Eissner. He lost both parents early in life, his father in the War and later his mother at the age of 15. He attended elementary school in his hometown (1937–1941) and high school in both Görlitz (1941–1945) and Lüdenscheid (1946–1951). His higher education was at Göttingen University (Preliminary Diploma in physics, 1954) and Tübingen University (Diploma under Professor Dr. Hubert Krüger, 1959, and doctorate degree under Professor Dr. Gerhard Elwert, 1967). His doctoral thesis dissertation was entitled “Rechnungen zur Elektronenstoßanregung der M-Schale von Wasserstoff und zur Polarisation des Stoßleuchtens der H𝛼 -Linie” (Calculations for the electron collision excitation of the M-shell of hydrogen and for the polarization of the collisionally excited H𝛼 line), which he presented in preliminary form at the Third International Conference on the Physics of Electronic and Atomic Collisions (ICPEAC, 22–26 July 1963) held at University College London (UCL) [1]. For most of Werner’s career, he was a member of two major research groups in atomic physics led by Professor Michael J. Seaton FRS at UCL and by Professor Philip G. Burke FRS at Queen’s University Belfast (QUB) and Daresbury Laboratory (DL).