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Author Nikolaev, A.V.; Michel, K.H.
Title Many electron- and hole terms of molecular ions C60n\pm Type A1 Journal article
Year 2003 Publication Coupling In Chemistry And Physics Abbreviated Journal Adv Quantum Chem
Volume 44 Issue Pages 305-312
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000188940800019 Publication Date 2004-05-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0065-3276; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.196 Times cited 1 Open Access
Notes Approved Most recent IF: 1.196; 2003 IF: 0.375
Call Number UA @ lucian @ c:irua:104131 Serial 1942
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Author Michel, K.H.; Verberck, B.; Nikolaev, A.
Title Mercator maps of orientations of a C60 molecule in single-walled nanotubes with distinct radii Type A1 Journal article
Year 2005 Publication AIP conference proceedings Abbreviated Journal
Volume 786 Issue Pages 69-72
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the confinement of a C-60 molecule encapsulated in a cylindrical nanotube as a function of the tube radius. Drawing the Mercator maps of the potential, we find two distinct molecular orientations; for tubes with small radii, R-T less than or similar to 7 angstrom, a fivefold axis of the molecule coincides with the tube long axis, for larger radii, R-T less than or similar to 8 angstrom, a threefold axis of the molecule coincides with the tube long axis. These different orientations are caused by the relative importance of the repulsive and the attractive parts of the van der Waals potentials of the molecule with the tube wall for small and large tubes respectively. Experimental evidence is provided by the apparent splitting of A(g) modes of the C-60 molecule in resonant Raman scattering.
Address
Corporate Author Thesis
Publisher Amer inst physics Place of Publication Melville Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0094-243x ISBN Additional Links UA library record; WoS full record;
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:94738 Serial 1993
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Author Zieliński, P.; Michel, K.H.
Title Microscopic model of surfaces in orientationally disordered ionic crystals : the (001) surface of KCN Type A1 Journal article
Year 1992 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 46 Issue 8 Pages 4806-4815
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract The crystallographic structure and the distribution of orientations of molecular ions are studied near the surface in an orientationally disordered crystal with the use of a Green-function formalism. The orientational degrees of freedom are treated by means of symmetry-adapted functions of angular coordinates. The structure of the (001) surface of KCN in its cubic fcc phase is then predicted using the existing data on the interaction of the ions K+ and CN-. A local antiferroelectric and antiferroelastic order i shown to exist in the surface region. The magnitude of the order and the spatial extent of the ordered re ion increase as the temperature approaches the point of the phase transition to the ordered phase. The,influence of the external electric field on the structure of the surface is predicted.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1992JK72500049 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.736 Times cited 4 Open Access
Notes Approved PHYSICS, CONDENSED MATTER 16/67 Q1 #
Call Number UA @ lucian @ c:irua:2974 Serial 2029
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Author Callebaut, A.K.; Michel, K.H.
Title Microscopic theory of orientational disorder and lattice instability in solid C70 Type A1 Journal article
Year 1995 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 52 Issue 21 Pages 15279-15290
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract We have developed a microscopic theory which describes the orientational dynamics of C-70 molecules and its coupling to lattice displacements in the face-centered-cubic phase of C-70 fullerite. The single-molecule orientational density distribution in the disordered phase is calculated. The ferroelastic transition to the rhombohedral phase is investigated. The discontinuity of the orientational order parameter at the phase transition is calculated. It is found that the transition leads to a stretching of the primitive unit cell along a [111] cubic direction. A softening of the elastic constant c(44) at the transition is predicted.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1995TK97900042 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.736 Times cited 20 Open Access
Notes Approved PHYSICS, APPLIED 28/145 Q1 #
Call Number UA @ lucian @ c:irua:104421 Serial 2031
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Author Michel, K.H.; Copley, J.R.D.; Neumann, D.A.
Title Microscopic theory of orientational disorder and the orientational phase transition in solid C60 Type A1 Journal article
Year 1992 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 68 Issue 19 Pages 2929-2932
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract We have developed a microscopic theory which describes the orientational dynamics of C60 molecules in the face-centered-cubic phase of C60 fullerite. The molecular interaction potential and the crystal-field potential are formulated in terms of symmetry-adapted rotator functions. The phase transition to the Pa3BAR structure is driven by an active multipolar mode of T2g symmetry belonging to the l = 10 manifold. The Birman criterion is satisfied. The transition is found to be of first order.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos A1992HT64800019 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.512 Times cited 94 Open Access
Notes Approved
Call Number UA @ lucian @ c:irua:95492 Serial 2032
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Author Nikolaev, A.V.; Michel, K.H.
Title Microscopic theory of quadrupolar oredring in TmTe Type A1 Journal article
Year 2001 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 63 Issue Pages 1-10
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000167402100025 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 7 Open Access
Notes Approved Most recent IF: 3.836; 2001 IF: NA
Call Number UA @ lucian @ c:irua:36882 Serial 2033
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Author Nikolaev, A.V.; Michel, K.H.
Title Microscopic theory of the rhombohedral phase and transition to the monoclinic phase of solid C70 Type A1 Journal article
Year 1996 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 54 Issue 18 Pages 12733-12743
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract Starting from a model of microscopic interactions between C-70 molecules, we have developed a theory which describes the orientational dynamics and its coupling to lattice displacements in the rhombohedral phase of C-70 fullerite. The Landau free energy is calculated. We obtain a first-order phase transition to a monoclinic structure with the space group P2(1)/m. The transition is driven by the condensation of orientational quadrupoles at the F point of the Brillouin zone of the rhombohedral lattice. We find no evidence that the monoclinic structure is connected with the freezing in of orientations around the fivefold molecular axis. We calculate the lattice strains that are associated with the transition to the monoclinic structure. The theory is compared with a range of experimental data on the phase transition.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1996VT68200028 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.736 Times cited 5 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:16357 Serial 2034
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Author Lamoen, D.; Michel, K.H.
Title Microscopic theory of thermoelastic phenomena and pressure dependence in solid C60 Type A1 Journal article
Year 1993 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 48 Issue 2 Pages 807-813
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract A microscopic theory for the coupling of molecular orientations with acoustic lattice displacements is proposed. The relevant interaction is quadratic in the orientational-order-parameter variables and linear in longitudinal strains. The coupling is evaluated for a complex molecular structure. The intermolecular potential is obtained from interaction centers placed at nuclei and at the centers of interatomic bonds. The free energy is derived and the experimental consequences of the theory are studied. The Clausius-Clapeyron equation for orientational melting is obtained. The theory explains the decrease of the lattice constant at the first-order phase transition and the increase of the transition temperature with applied pressure.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1993LM88500014 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.736 Times cited 32 Open Access
Notes Approved PHYSICS, CONDENSED MATTER 16/67 Q1 #
Call Number UA @ lucian @ c:irua:5779 Serial 2035
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Author Michel, K.H.
Title Molecular structure and orientational ordering in solid C60 Type A1 Journal article
Year 1992 Publication The journal of chemical physics Abbreviated Journal J Chem Phys
Volume 97 Issue 7 Pages 5155-5162
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract A microscopic theory, which describes the orientational dynamics of C60 molecules in the face-centered cubic phase of C60-fullerite, is formulated or the case of a complex molecular structure. Interaction centers which comprise atoms, double bonds, and single bonds as molecular constituents contribute to the intermolecular potential. Orientation dependent physical properties are described in terms of symmetry-adapted rotator functions. It is found that a same set of rotator functions is sufficient even in the case of a complex molecular structure. Phase transition temperatures are discussed for various models of molecular structure.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos A1992JR33800062 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9606; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.952 Times cited 20 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:2973 Serial 2185
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Author Copley, J.R.D.; Michel, K.H.
Title Multiple orientational order parameters in solid C60 Type A1 Journal article
Year 1997 Publication Physica: B : condensed matter T2 – International Conference on Neutron Scattering, AUG 17-21, 1997, TORONTO, CANADA Abbreviated Journal Physica B
Volume 241 Issue Pages 454-455
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract The transition Fm (3) over bar m -->Pa (3) over bar in solid C-60 is driven by the condensation of orientational modes belonging to X-5(+) irreducible representations (irreps) of Fm (3) over bar m. Taking into account irreps up to the manifold l = 12, we have studied the primary and secondary orientational order parameters loops). We have numerically solved the coupled molecular field equations for these oops and calculated the temperature dependence of Bragg reflection intensities. (C) 1998 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000074062600130 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526; ISBN Additional Links UA library record; WoS full record
Impact Factor 1.386 Times cited Open Access
Notes Approved Most recent IF: 1.386; 1997 IF: 0.991
Call Number UA @ lucian @ c:irua:104360 Serial 2228
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Author Michel, K.H.; Verberck, B.; Nikolaev, A.V.
Title Nanotube field and one-dimensional fluctuations of C60 molecules in carbon nanotubes Type A1 Journal article
Year 2005 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
Volume 48 Issue 1 Pages 113-124
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000233998600016 Publication Date 2005-12-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6028;1434-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.461 Times cited 25 Open Access
Notes Approved Most recent IF: 1.461; 2005 IF: 1.720
Call Number UA @ lucian @ c:irua:56408 Serial 2279
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Author Verberck, B.; Michel, K.H.
Title Nanotube field and orientational properties of C70 molecules in carbon nanotubes Type A1 Journal article
Year 2007 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 75 Issue 4 Pages 045419,1-14
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract The orientation of a C(70) fullerene molecule encapsulated in a single-walled carbon nanotube (SWCNT) depends on the tube radius. First we confirm that chirality effects do not affect the orientation as well by comparing discrete atomistic calculations with the results of a continuous tube approximation for a variety of SWCNTs. The molecular and the tube symmetry are exploited by using symmetry-adapted rotator functions. We accurately determine the optimal molecular orientation as a function of the tube radius; for low (less than or similar to 7 A) and high (greater than or similar to 7.2 A) tube radii, lying and standing molecular orientations are recovered, respectively. In between, we observe a transition regime. In addition, we consider off-axis positions. We perform a one-dimensional liquid description of a chain of on-axis C(70) molecules inside a SWCNT. All results agree well with recent x-ray diffraction experiments.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000243895600128 Publication Date 2007-01-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 23 Open Access
Notes Approved Most recent IF: 3.836; 2007 IF: 3.172
Call Number UA @ lucian @ c:irua:63752 Serial 2280
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Author Verberck, B.; Michel, K.H.
Title Nanotube field of C60 molecules in carbon nanotubes: atomistic versus continuous approach Type A1 Journal article
Year 2006 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 74 Issue 4 Pages 045421,1-14
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000239426800113 Publication Date 2006-07-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 31 Open Access
Notes Approved Most recent IF: 3.836; 2006 IF: 3.107
Call Number UA @ lucian @ c:irua:60090 Serial 2281
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Author Verberck, B.; Michel, K.H.
Title Nanotube field of C60 and C70 molecules in carbon nanotubes Type A1 Journal article
Year 2007 Publication International journal of quantum chemistry Abbreviated Journal Int J Quantum Chem
Volume 107 Issue 13 Pages 2294-2319
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000249459800002 Publication Date 2007-02-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-7608;1097-461X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.92 Times cited 6 Open Access
Notes Approved Most recent IF: 2.92; 2007 IF: 1.368
Call Number UA @ lucian @ c:irua:65785 Serial 2282
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Author Copley, J.R.D.; Michel, K.H.
Title Neutron and X-ray-scattering cross sections of orientationally disordered solid C60 Type A1 Journal article
Year 1993 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 5 Issue 26 Pages 4353-4370
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract Differential cross sections for neutron and x-ray scattering have been derived for the orientationally disordered phase of solid C60. Interaction centres are placed at nuclei and at the centres of interatomic bonds. Bragg and diffuse scattering cross sections, for single crystals and for powders, are formulated using symmetry-adapted rotator functions. Thermal averages are calculated taking account of crystal field effects. Thermally averaged orientational distribution functions have also been calculated.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos A1993LK74100008 Publication Date 2002-08-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-8984;1361-648X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.346 Times cited 34 Open Access
Notes Approved MATERIALS SCIENCE, MULTIDISCIPLINARY 96/271 Q2 #
Call Number UA @ lucian @ c:irua:102972 Serial 2298
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Author Verberck, B.; Nikolaev, A.V.; Michel, K.H.
Title Orientational charge density waves and the metal-insulator transition in polymerized KC60 Type A1 Journal article
Year 2004 Publication AIP conference proceedings Abbreviated Journal
Volume 723 Issue Pages 339-342
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract Polymerized KC60 undergoes a structural phase transition accompanied by a metal-insulator transition around 50 K. To explain the structural aspect, a mechanism involving small orientational deviations of the valence electron density on every C-60 monomer orientational charge density waves (OCDWs) – has already been proposed earlier. In the present work, we address the metal-insulator transition using the OCDW concept. We are inspired by the analogy between a polymer chain exhibiting an OCDW and a linear atomic chain undergoing a static lattice deformation doubling the unit cell: such a deformation implies a band gap at the zone boundary, yielding an insulating state (Peierls instability). Within our view, a similar mechanism occurs in polymerized KC60; the OCDW plays the role of the lattice deformation. We present tight-binding band structure calculations and conclude that the metal-insulator transition can indeed be explained using OCDWs, but that the threedimensionality of the crystal plays an unexpected key role.
Address
Corporate Author Thesis
Publisher Place of Publication New York Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0094-243x ISBN Additional Links UA library record; WoS full record;
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:94831 Serial 2513
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Author Verberck, B.; Nikolaev, A.V.; Michel, K.H.
Title Orientational charge density waves and the metal-insulator transition in polymerized KC60 Type A1 Journal article
Year 2005 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 71 Issue 16 Pages 165117-11
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract A theoretical model is presented for the description of the metal-insulator transition which accompanies the structural phase transition at T approximate to 50 K in polymerized KC60. The model involves orientational charge density waves (along the C-60 polymer chains) which were introduced previously for a description of the structural phase transition. A satisfactory qualitative and quantitative understanding is obtained when the three-dimensionality of the crystal and the presence of the K+ counterions is properly taken into account.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000228763100035 Publication Date 2005-04-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 1 Open Access
Notes Approved Most recent IF: 3.836; 2005 IF: 3.185
Call Number UA @ lucian @ c:irua:104076 Serial 2514
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Author Michel, K.H.; Lamoen, D.; David, W.I.F.
Title Orientational order and disorder in solid C60 : theory and diffraction experiments Type A1 Journal article
Year 1995 Publication Acta crystallographica: section A: foundations of crystallography Abbreviated Journal Acta Crystallogr A
Volume 51 Issue 3 Pages 365-374
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract Starting from a microscope model of the intermolecular potential, a unified description is presented of the Bragg scattering law in the orientationally disordered and in the ordered phase of solid C-60. The orientational structure factor is expanded in terms of symmetry-adapted surface harmonics. The expansion coefficients are calculated from theory and compared with experiment Their temperature evolution is studied in the disordered phase at the 260 K transitions and in the ordered phase. In the ordered phase, new results from high-resolution neutron powder diffraction are given. In the disordered phase, space group Fm $($) over bar$$ 3m, the reflections have A(1g) symmetry; in the ordered phase, space group Pa $$($) over bar 3, reflections of T-2g symmetry appear and in addition the A(1g) reflections are renormalized. The orientational density distribution is calculated. The effective crystal-field potential is constructed, its temperature evolution in the ordered phase is studied and related to the occurrence of an orientational glass.
Address
Corporate Author Thesis
Publisher Place of Publication Copenhagen Editor
Language Wos A1995RB59400018 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0108-7673; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.307 Times cited 14 Open Access
Notes Approved CHEMISTRY, MULTIDISCIPLINARY 65/163 Q2 # CRYSTALLOGRAPHY 10/26 Q2 #
Call Number UA @ lucian @ c:irua:12189 Serial 2518
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Author Michel, K.H.; Verberck, B.
Title Phonon dispersions and piezoelectricity in bulk and multilayers of hexagonal boron nitride Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 11 Pages 115328-115328,14
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract A unified theory of phonon dispersions and piezoelectricity in bulk and multilayers of hexagonal boron nitride (h-BN) is derived. The dynamical matrix is calculated on the basis of an empirical force constant model of intralayer valence and interlayer van der Waals interactions. Coulomb interactions are calculated by Ewalds method, adapted for the three-dimensional (3D) and the multilayer case. The deformation of the ionic charge distribution with long-wave lattice displacements is taken into account. Special attention is devoted to the nonanalytic long-range Coulomb contribution to the dynamical matrix which is different for the 3D crystal and the multilayer case. Consequently there is a splitting of the transverse optical (TO) and longitudinal optical (LO) phonon branches of E1u symmetry and a discontinuity of the A2u branch at the Γ point in 3D h-BN. No such splitting and discontinuity at Γ are present in multilayer crystals with a finite number N of layers. There a diverging bundle of N overbending optical phonon branches emerges from Γ. Borns long-wave theory is applied and extended for the study of piezoelectricity in layered crystals. While 3D h-BN and h-BN multilayers with an even number of layers (symmetry D6h) are not piezoelectric, multilayers with an uneven number of Nu layers (symmetry D3h) are piezoelectric; the piezoelectric coefficient e1,11 is inversely proportional to Nu.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000288783700005 Publication Date 2011-03-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 82 Open Access
Notes ; Discussions with G. Heger, B. Partoens, and F. M. Peeters are gratefully acknowledged. This work has been supported by the Flemish Science Foundation (FWO-V1) and the Bijzonder Onderzoeksfonds, Universiteit Antwerpen (BOF-UA). ; Approved Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:89602 Serial 2603
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Author Bussmann-Holder, A.; Dalal, N.; Michel, K.H.
Title Polarizability induced cooperative proton ordering, coexistence of order/disorder and displacive dynamics and isotope effects in hydrogen-bonded systems Type A1 Journal article
Year 2000 Publication The journal of physics and chemistry of solids T2 – Williamsburg Workshop on Ferroelectrics 99, JAN 31-FEB 03, 1999, WILLIAMSBURG, VIRGINIA Abbreviated Journal J Phys Chem Solids
Volume 61 Issue 2 Pages 271-274
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract Despite the general belief that hydrogen-bonded ferro- and antiferroelectrics undergo a pure order/disorder transition at the structural instability, new NMR data and a new theoretical concept yield convincing evidence that a pronounced displacive component is present in these systems, which modifies substantially the temperature dependencies of the tunnel and lattice mode frequencies. The experiments and their interpretation are presented. (C) 1999 Elsevier Science Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Pergamon-elsevier science ltd Place of Publication Oxford Editor
Language Wos 000084147000020 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3697; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.059 Times cited 8 Open Access
Notes Approved Most recent IF: 2.059; 2000 IF: 1.003
Call Number UA @ lucian @ c:irua:103469 Serial 2660
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Author Nikolaev, A.V.; Michel, K.H.
Title Quantum charge density fluctuations and the γ-α phase transition in Ce Type A1 Journal article
Year 1999 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
Volume 9 Issue Pages 619-634
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000081615500009 Publication Date 2002-08-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6028; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.461 Times cited 19 Open Access
Notes Approved Most recent IF: 1.461; 1999 IF: 1.705
Call Number UA @ lucian @ c:irua:28504 Serial 2774
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Author Michel, K.H.; Verberck, B.
Title Rigid-plane phonons in layered crystals Type A1 Journal article
Year 2012 Publication Physica status solidi: B: basic research Abbreviated Journal Phys Status Solidi B
Volume 249 Issue 12 Pages 2604-2607
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract The determination of the layer number ${\cal N}$ in nanoscale thin layered crystals is a challenging problem of technological relevance. In addition to innovative experimental techniques, a thorough knowledge of the underlying lattice dynamics is required. Starting from phenomenological atomic interaction potentials we have carried out an analytical study of the low-frequency optical phonon dispersions in layered crystals. At the gamma point of the two-dimensional Brillouin zone the optical phonon frequencies correspond to rigid-plane shearing and compression modes. We have investigated graphene multilayers (GML) and hexagonal boron-nitride multilayers (BNML). The frequencies show a characteristic dependence on ${\cal N}$. The results which are represented in the form of fan diagrams are very similar for both materials. Due to charge neutrality within layers Coulomb forces play no role, only van der Waals forces between nearest neighbor layers are relevant. The theoretical results agree with recent low-frequency Raman results on rigid-layer modes [Tan et al., Nature Mater. 11, 294 (2012)] in GML and double-resonant Raman scattering data on rigid-layer compression modes [Herziger et al., Phys. Rev. B 85, 235447 (2012)] in GML. (C) 2012 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000312215300072 Publication Date 2012-11-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-1972; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.674 Times cited 1 Open Access
Notes ; This work has been supported by the Flemish Science Foundation (FWO-Vl) and the Bijzonder Onderzoeksfonds, Universiteit Antwerpen (BOF-UA). ; Approved Most recent IF: 1.674; 2012 IF: 1.489
Call Number UA @ lucian @ c:irua:105992 Serial 2907
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Author Michel, K.H.
Title Sequence of orientational phase transitions in solid C60 Type A1 Journal article
Year 1992 Publication Chemical physics letters Abbreviated Journal Chem Phys Lett
Volume 193 Issue Pages 478-480
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1992HZ32900006 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0009-2614; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.897 Times cited 14 Open Access
Notes Approved MATERIALS SCIENCE, MULTIDISCIPLINARY 96/271 Q2 #
Call Number UA @ lucian @ c:irua:2971 Serial 2985
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Author Nikolaev, A.V.; Michel, K.H.
Title Superexchange and electron correlations in alkali fullerides AC60, A=K, Rb, Cs Type A1 Journal article
Year 2005 Publication The journal of chemical physics Abbreviated Journal J Chem Phys
Volume 122 Issue 6 Pages 064310-64314
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract Superexchange interactions in alkali fullerides AC(60) are derived for C-60 molecular ions separated by interstitial alkali-metal ions. We use a multiconfiguration approach which comprises the lowest molecular orbital states of the C-60 molecule and the excited s and d states of the alkali-metal atom A. Interactions are described by the valence bond (Heitler-London) method for a complex (C-60 – A – C-60) – with two valence electrons. The electronic charge transfer between the alkali-metal atom and a neighboring C-60 molecule is not complete. The occupation probability of excited d and s states of the alkali atom is not negligible. In correspondence with the relative positions of the C-60 molecules and A atoms in the polymer crystal, we consider 180degrees and 90degrees (angle) superexchange pathways. For the former case the ground state is found to be a spin singlet separated from a triplet at similar to20 K. For T < 20 K there appear strong spin correlations for the 180degrees superexchange pathway. The results are related to spin lattice relaxation experiments on CsC60 in the polymerized and in the quenched cubic phase. (C) 2005 American Institute of Physics.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000226918100018 Publication Date 2005-02-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9606; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.965 Times cited 11 Open Access
Notes Approved Most recent IF: 2.965; 2005 IF: 3.138
Call Number UA @ lucian @ c:irua:102740 Serial 3377
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Author Michel, K.H.; Verberck, B.; Hulman, M.; Kuzmany, H.; Krause, M.
Title Superposition of quantum and classical rotational motions in Sc2C2@C84 fullerite Type A1 Journal article
Year 2007 Publication The journal of chemical physics Abbreviated Journal J Chem Phys
Volume 126 Issue 6 Pages 064304,1-15
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000244250200008 Publication Date 2007-02-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9606; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.965 Times cited 14 Open Access
Notes Approved Most recent IF: 2.965; 2007 IF: 3.044
Call Number UA @ lucian @ c:irua:63628 Serial 3381
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Author Nikolaev, A.V.; Michel, K.H.
Title Symmetry lowering at the structural phase transitions in NpO2 and UO2 Type A1 Journal article
Year 2003 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 68 Issue 5 Pages 054112-054112,7
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract The structural phase transitions with electric-quadrupole long-range order in NpO2 (Fm (3) over barm-->Pn (3) over barm) and UO2 (Fm (3) over barm-->Pa (3) over bar) are analyzed from a group theoretical point of view. In both cases, the symmetry lowering involves three quadrupolar components belonging to the irreducible representation T-2g (Gamma(5)) of O-h and condensing in a triple-q structure at the X point of the Brillouin zone. The Pa (3) over bar structure is close to Pn (3) over barm, but allows for oxygen displacements. The Pa (3) over bar ordering leads to an effective electrostatic attraction between electronic quadrupoles while the Pn (3) over barm ordering results in a repulsion between them. It is concluded that the Pn (3) over barm structure can be stabilized only through some additional process such as strengthening of the chemical bonding between Np and O. We also derive the relevant structure-factor amplitudes for Pn (3) over barm and Pa (3) over bar, and the effect of domains on resonant x-ray scattering experiments.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000185240100038 Publication Date 2003-08-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 15 Open Access
Notes Approved Most recent IF: 3.836; 2003 IF: NA
Call Number UA @ lucian @ c:irua:94847 Serial 3405
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Author Verberck, B.; Michel, K.H.; Nikolaev, A.V.
Title The C60 molecules in (C60)N@SWCNT peapods: crystal field, intermolecular interactions and dynamics Type A1 Journal article
Year 2006 Publication Fullerenes, nanotubes, and carbon nanostructures Abbreviated Journal Fuller Nanotub Car N
Volume 14 Issue 2/3 Pages 171-178
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000238762900006 Publication Date 2006-06-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1536-383X;1536-4046; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.35 Times cited 10 Open Access
Notes Approved Most recent IF: 1.35; 2006 IF: 0.462
Call Number UA @ lucian @ c:irua:60025 Serial 3518
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Author Bussmann-Holder, A.; Michel, K.H.
Title The isotope effect in hydrogen-bonded systems Type A1 Journal article
Year 1998 Publication International journal of modern physics: B: condensed matter physics, statistical physics, applied physics T2 – 1st International Conference on New Theories, Discoveries, and, Applications of Superconductors and Related Materials (New3SC-1), FEB 19-24, 19 Abbreviated Journal Int J Mod Phys B
Volume 12 Issue 29-31 Pages 3406-3408
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract The giant isotope effect on the ferro- and antiferroelectric transition temperature upon deuteration of hydrogen-bonded systems is well known experimentally since various decades. Yet, theoretically only recently a microscopic understanding of this effect has been achieved which, specifically, took into account the geometry of the O ... H ... O bond. The implications of this modeling are multiple as numerous hydrogen-bonded organic systems show the same effects as ferro- and antiferroelectrics, i.e., cooperative proton tunneling at a well-defined temperature.
Address
Corporate Author Thesis
Publisher Place of Publication Singapore Editor
Language Wos 000079114500104 Publication Date 2003-10-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0217-9792;1793-6578; ISBN Additional Links UA library record; WoS full record
Impact Factor 0.736 Times cited Open Access
Notes Approved Most recent IF: 0.736; 1998 IF: 0.987
Call Number UA @ lucian @ c:irua:102920 Serial 3589
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Author Verberck, B.; Nikolaev, A.V.; Michel, K.H.
Title Theoretical model for the structural phase transition at the metal-insulator transition in polymerized KC60 Type A1 Journal article
Year 2002 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 66 Issue 16 Pages 165425-165425,14
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract The recently discovered structural transition in polymerized KC60 at about 50 K results in a doubling of the unit cell volume and accompanies the metal-insulator transition. Here we show that the ((a) over right arrow+(c) over right arrow,(b) over right arrow,(a) over right arrow-(c) over right arrow) superstructure results from small orientational charge density waves along the polymer chains and concomitant displacements of the surrounding K+ ions. The effect is specific for the space group Pmnn of KC60 and is absent in RbC60 and CsC60 (space group I2/m). The mechanism is relevant for the metal-insulator transition.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000179286400135 Publication Date 2002-10-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 10 Open Access
Notes Approved Most recent IF: 3.836; 2002 IF: NA
Call Number UA @ lucian @ c:irua:94907 Serial 3608
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Author Michel, K.H.; Verberck, B.
Title Theoretical phonon dispersions in monolayers and multilayers of hexagonal boron-nitride Type A1 Journal article
Year 2009 Publication Physica status solidi: B: basic research Abbreviated Journal Phys Status Solidi B
Volume 246 Issue 11/12 Pages 2802-2805
Keywords (down) A1 Journal article; Condensed Matter Theory (CMT)
Abstract Starting from an empirical force constant model of valence interactions and calculating by Ewald's method the electrostatic force constants, we derive the dynamical matrix for a monolayer and for multilayer systems of hexagonal boron nitride (h-BN). Solution of the secular problem leads to the corresponding phonon dispersion relations. The interplay between valence forces and Coulomb forces is discussed. A comparison with previous results on graphene and graphene multilayers is made. Our spectra on the h-BN monolayer are rather similar to previous ab initio theory results. Comparison is also made with Raman and infrared experimental results.
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000272904100091 Publication Date 2009-11-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-1972; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.674 Times cited 10 Open Access
Notes Approved Most recent IF: 1.674; 2009 IF: 1.150
Call Number UA @ lucian @ c:irua:80673 Serial 3609
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