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AbstractAbstract
[en] The doubly excited 1,3D0 resonance states of Ps- associated with N=3, N=4 and N=5 Ps thresholds have been investigated using highly accurate correlated wave functions with exponents generated by a quasi-random process. Resonance parameters (both resonance positions and widths) are extracted in the framework of the stabilization method and the complex coordinate rotation method. In addition to many Feshbach resonances below the various Ps thresholds, we have identified two 1D0 shape resonances with one each lying above the N=3 and N=4 thresholds, respectively, and two 3D0 shape resonances with one each lying above the N=3 and N=5 thresholds, respectively. The 1D0 shape resonance associated with N=3 Ps threshold and some other Feshbach resonances are reported for the first time in the literature. (authors)
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Available from doi: http://dx.doi.org/10.1140/epjd/e2010-00002-3; 43 refs.
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Journal Article
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European Physical Journal. D, Atomic, Molecular, Optical and Plasma Physics; ISSN 1434-6060;
; v. 57(no.1); p. 13-19

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AbstractAbstract
[en] The fine-structure intervals of the lowest two triplet D states of 4He have been obtained by a new method: Ground-state atoms are excited by a discharge to the triplet metastable state, which then undergoes a two-step optical excitation to the triplet D states, where level-crossing measurements are made. The experimental results for 3D1-3D3 (MHz) are 1400.67 plus-or-minus 0.29 and 591.25 plus-or-minus 0.14 for the 3 3D and 4 3D states, respectively; for 3D2-3D3 (MHz) they are 75.97 plus-or-minus 0.23 and 36.15 plus-or-minus 0.24 for 3 3D and 4 3D. These values are much more precise than the previously available data, obtained by optical, particle-bombardment level crossing, or beam-foil quantum-beat spectroscopy, and are consistent with the previous data except for one case, where a previous measurement of 3 3D2-3 3D3 by electron bombardment level-crossing spectroscopy is believed to be in error. These new experimental values for the fine structures of the triplet D state of 4He clearly indicate the inadequateness of existing theoretical calculations of these fine structures
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Journal Article
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Physical Review. A; v. 12(2); p. 539-550
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Voloshin, M.B.
Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Teoreticheskoj i Ehksperimental'noj Fiziki1977
Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Teoreticheskoj i Ehksperimental'noj Fiziki1977
AbstractAbstract
[en] Theoretical estimates of the radiative and annihilative decays of the 11D2 charmonium level are discussed within the framework of the nonrelativistic potential model of charmonium. It is argued that the state CHI(3.45) possibly seen in PSI' radiative decay cannot be identified with the 11D2 charmonium level
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1977; 11 p; 9 refs.
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AbstractAbstract
[en] Highlights: • Two 3d orbitals of iron are critical for activating methane, explaining why high spin atomic iron is inactive. • Emptying the 4s orbital of iron increases activity. • The coordination of Iron can effect its ability to activate methane. Theoretical studies on the activation of the C-H bond in methane by an Iron atom bound to four different sites on a silica model support indicate that the lowest activation barrier is found for the case when the Fe is bound to three exposed silicon sites. A molecular orbital analysis reveals that the transition state is stabilized by two filled 3d orbitals that mix with the HOMO and LUMO of methane respectively, indicating how the energy and occupation of the 3d orbitals determine the reaction barrier. The studies offer a strategy for identifying candidates with optimal electronic structure for maximizing C-H bond activation using non-precious metals.
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Source
S0009261416305449; Available from http://dx.doi.org/10.1016/j.cplett.2016.07.053; Copyright (c) 2016 Elsevier B.V. All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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AbstractAbstract
[en] From a study of experimental phase shifts for p+4He elastic scattering at proton energies below 50 MeV we conclude that small D-state admixtures to the dominant S-state configuration exist in the 4He ground state. This result is obtained by evaluating a forward dispersion relation for the p+4He spin-flip scattering amplitude
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Physical Review Letters; v. 34(13); p. 830-833
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AbstractAbstract
[en] Doubly excited or Feshbach-type resonances in helium-like systems have been calculated using the complex-rotation method. Using Hylleraas-type wavefunctions up to 680 terms, we predict resonance parameters (both resonance positions and widths) below the N = 3, 4 thresholds of the hydrogenic systems with the nuclear charge from Z = 2-10. The present results for the lowest 1.3Do states in helium below the N = 3 threshold agree well with those of Lindroth. Comparisons are also made with the other calculations for Z > 2 in the literature. (Author)
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Journal Article
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Journal of Physics. B, Atomic, Molecular and Optical Physics; ISSN 0953-4075;
; CODEN JPAPEH; v. 30(16); p. 3597-3609

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[en] The D1 resonance line of francium, which corresponds to the transition 7s2Ssub(1/2)-7p2Psub(1/2), has been observed in a laser spectroscopy experiment performed on line with the mass separator ISOLDE at C.E.R.N. on the isotope of mass 212. A preliminary measurement of the wavelength has been carried out: lambdasub(D1)(212Fr) = (816.90+-0.02) mm, and the fine structure splitting of the excited level has been deduced using a previous measurement of the lambdasub(D2):Δσsub(FS)(7p2Psub(3/2)-7p2Psub(1/2) = (1.686.8+-0.5) cm-1
[fr]
La raie de resonance D1 du francium correspondant a la transition 7s2Ssub(1/2)-7p2Psub(1/2) a ete observee dans une experience de spectroscopie laser faite en ligne derriere le separateur de masse ISOLDE du C.E.R.N. sur l'isotope de masse 212. Une premiere mesure de la longueur d'onde a ete effectuee: lambdasub(D1)(212Fr) = (816,90+-0,02) nm, et l'ecart de structure fine du niveau excite a pu etre deduit en utilisant une mesure faite precedemment de lambdasub(D2):Δσsub(SF)(7p2Psub(3/2)-7p2Psub(1/2) = (1686,8+-0,5) cm-1Original Title
Mise en evidence et mesure de la longueur d'onde de la raie de resonance D1 du francium
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Comptes Rendus des Seances de l'Academie des Sciences. Serie 2; ISSN 0249-6305;
; v. 299(17); p. 1157-1160

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AbstractAbstract
No abstract available
Original Title
Zero-field level crossing, principal quantum numbers n = 3, 4, 5, and 6
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Physical Review Letters; v. 30(26); p. 1286-1288
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Picker, H.S.; Stephenson, G.J. Jr.
Maryland Univ., College Park (USA). Dept. of Physics and Astronomy1974
Maryland Univ., College Park (USA). Dept. of Physics and Astronomy1974
AbstractAbstract
No abstract available
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Oct 1974; 35 p
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[en] Lifetime observations have been made on 49 energy levels of helium. Good overall agreement with theory is obtained, with significant exceptions, the most striking of which are the 31D and 33D states, where 50% discrepancies with theory and some of the older measurements are found. The new measurements are, however, in harmony with recent results using the Hanle effect. The existance of the upper-state process is clearly delineated by the results of n>6. (author)
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Journal of Quantitative Spectroscopy and Radiative Transfer; v. 15(11); p. 1017-1024
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