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AbstractAbstract
[en] All interatomic distances [D(calc.)j] in Pbnm silicate olivines are linearly related with M1 and M2 site occupancy through a relationship of the type: D(calc.)j = ΣsΣiωsub(ijs)Xsub(is) + ξj, where ωsub(ijs), ξj are adjustable coefficients, and Xsub(is) are the fractions of ith ion in site s. The precision attained by this relation, based on seven divalent ions (Mg, Fe, Ca, Mn, Co, Ni, Zn), is satisfactory, the mean difference vertical strokeD(calc.) - D(obs.)vertical stroke always being less than 0.005 A for each distance. Moreover, all ωsub(ijs) coefficients are related to properties of ions through a relation of the type: ωsub(ijs) = K1sub(js)(ΣZm=1Im)i-1/2+K2sub(js)αif1/4 + K3sub(js), where ΣZm=1Im is the sum of the ionization potentials for the ith ion up to its valency state (Z), αif is its polarizability, and K1sub(js), K2sub(js) and K3sub(js) are numerical constants. The existence of this strict dependency is predictable, based on the concept of effective nuclear charge and its relationship with polarizability and ionic potentials. As a consequence, all interatomic distances may be simulated through an equation of the type: D(calc.)j = ΣS{W1sub(js)Σi[Xsub(is)(ΣZm=1Im)i-1/2]} + Σs[W2sub(js)Σi(Xsub(is)αif1/4)] + W3j, where W1sub(js), W2sub(js) and W3j are adjustable parameters which directly involve the ionization potentials and polarizabilities of the ions. (orig.)
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Journal Article
Journal
Acta Crystallographica. Section B: Structural Science; ISSN 0108-7681;
; CODEN ASBSD; v. 46(2); p. 160-165

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[en] Published in summary form only
Original Title
Distancia intra-atomica versus volume atomico para o estado fundamental do H sub(2) cristalino
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Source
Almeida Fonseca, A.L. de (Brasilia Univ., DF (Brazil)); Koiler, B. (Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)); Brescansin, L.M. (Universidade Estadual de Campinas, SP (Brazil)) (and others); Sociedade Brasileira de Fisica, Rio de Janeiro, RJ (Brazil); 284 p; 1990; p. 235; 13. National Meeting on Condensed Matter Physics; Caxambu, MG (Brazil); 8-12 May 1990; Available from the Library of Comissao Nacional de Energia Nuclear, RJ, Brazil
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No abstract available
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Journal Article
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Journal of Chemical Physics; v. 60(5); p. 2195-2196
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AbstractAbstract
[en] A semiempirical method for calculating the polarizability of diatomic molecules in the entire range of possible values if their internuclear distance is proposed. The method is based on the functional dependence of the polarizability of a molecule on the internuclear distance R in the region of small R obtained in the previous paper, the known polarizabilities and their derivatives at the equilibrium position of the molecule nuclei, and also results of the model of polarized of atoms valid for large internuclear distances. The efficiency of the proposed method is tested for the hydrogen molecule for which reliable polarizability values are available in the wide range of internuclear distances. The proposed method is used for calculating the polarizabilities of the nitrogen and oxygen molecules. 17 refs., 6 figs., 1 tab
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Cover-to-cover Translation of Optika i Spektroskopiya (USSR); Translated from Optika i Spektroskopiya; 78: No. 1, 26-30(1995).
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Journal Article
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Translation
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[en] An accurate Patterson function, free of artifacts, is obtained by transforming low-energy electron diffraction I-V spectra at multiple incident angles. The demonstration is carried out using normal incidence measured spectra and calculated spectra at three angles of incidence. The errors between intensity spots in the Patterson function and known interatomic distances are less than 0.01 {angstrom} in the horizontal direction and 0.09 {angstrom} in the vertical direction. The reason for the high accuracy in the horizontal direction is given
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Source
Othernumber: PRLTAO000087000003036101000001; 034126PRL
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Journal Article
Journal
Physical Review Letters; ISSN 0031-9007;
; v. 87(3); p. 036101-036101.4

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AbstractAbstract
[en] The interatomic distances in the transition states of radical hydrogen atom abstraction reactions X.+HY → XH+Y. determined by quantum chemical calculations are systematized and generalized. It is shown that depending on the reaction centre structure, these reactions can be subdivided into classes with the same X...Y interatomic distance in each class. The transition state geometries found by the methods of intersecting parabolas and intersecting Morse curves are also presented. The X...H...Y fragments are almost linear, the hydrogen atom position being determined by the reaction enthalpy. The effects of triplet repulsion, electronegativities and radii of X and Y atoms, the presence of adjoining π-bonds, and steric effects on the X...Y interatomic distances are analyzed and characterized. The bibliography includes 62 references.
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Available from http://dx.doi.org/10.1070/RC2012v081n12ABEH004275; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
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Russian Chemical Reviews (Print); ISSN 0036-021X;
; v. 81(12); p. 1117-1132

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Saraswathy, P.; Sunanda, K., E-mail: saras@barc.gov.in2008
AbstractAbstract
[en] The B0u+-X0g+ and B1u-X1g transitions of 80Se2 and 78Se2 are reinvestigated. Several new bands are reported, especially for the B1u-X1g system, their vibrational numbering being confirmed by isotope shift studies. The Franck-Condon factors and r-centroid values are evaluated. By correlating the theoretically computed intensities with observed values, the internuclear distance dependence of the electronic transition moments of these two systems is determined for the first time
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Source
S0022-4073(07)00283-X; Available from http://dx.doi.org/10.1016/j.jqsrt.2007.09.017; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Record Type
Journal Article
Journal
Journal of Quantitative Spectroscopy and Radiative Transfer; ISSN 0022-4073;
; CODEN JQSRAE; v. 109(7); p. 1252-1259

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No abstract available
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Kirchmayr, H.R. (ed.) (Technische Univ., Vienna (Austria)); Oesterreichische Physikalische Gesellschaft, Vienna; 216 p; 1984; p. AP36; Electronic structure and properties of rare earth and actinide intermetallics; St. Poelten (Austria); 3-6 Sep 1984; Published in summary form only.
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[en] The parameters needed to calculate bond valences from bond lengths have been determined for 750 atom pairs using the Inorganic Crystal Structure Database. The most accurate 141 are listed and an algorithm is given which allows the calculation of the remainder as well as the calculation of parameters for over a thousand other bond types. Graphical bond-valence-bond-length correlations are presented for hydrogen bonds. (orig.)
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Journal Article
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Acta Crystallographica. Section B: Structural Crystallography and Crystal Chemistry; ISSN 0567-7408;
; v. 41(4); p. 244-247

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[en] The crystal structure of scandium dodecaboride is determined. The data obtained have confirmed that ScB12 has cubic f.c.c. structure, a=0.7402(3) nm. The results unambiguosly testify to the fact that ScB12 structure belongs to the UB12 type
Original Title
Kristallicheskaya struktura ScB12
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Journal Article
Journal
Izvestiya Akademii Nauk SSSR, Neorganicheskie Materialy; ISSN 0002-337X;
; CODEN IVNMA; v. 24(3); p. 506-507

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