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Records |
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Author |
Michel, K.H.; Neek-Amal, M.; Peeters, F.M. |
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Title |
Static flexural modes and piezoelectricity in 2D and layered crystals |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
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Volume |
253 |
Issue |
253 |
Pages |
2311-2315 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Piezo- and flexoelectricity are manifestations of electromechanical coupling in solids with potential applications in nanoscale materials. Naumov etal. [Phys. Rev. Lett. 102, 217601 (2009)] have shown by first principles calculations that a monolayer BN sheet becomes macroscopically polarized in-plane when in a corrugated state. Here, we investigate the interplay of layer corrugation and in-plane polarization by atomistic lattice dynamics. We treat the coupling between static flexural modes and in-plane atomic ion displacements as an anharmonic effect, similar to the membrane effect that is at the origin of negative thermal expansion in layered crystals. We have derived analytical expressions for the corrugation-induced static in-plane strains and the optical displacements with the resulting polarization response functions. Beyond h-BN, the theory applies to transition metal dichalcogenides and dioxides. Numerical calculations show that the effects are considerably stronger for 2D h-BN than for 2H-MoS2. |
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Publisher |
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Place of Publication |
Berlin |
Editor |
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Language |
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Wos |
000390339000002 |
Publication Date |
2016-10-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-1972 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.674 |
Times cited |
5 |
Open Access |
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Notes |
; The authors acknowledge useful discussions with L. Wirtz, A. Molina-Sanchez, and C. Sevik. This work was supported by the ESF-Eurographene project CONGRAN, and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 1.674 |
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Call Number |
UA @ lucian @ c:irua:140309 |
Serial |
4462 |
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Permanent link to this record |
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Author |
Michel, K.H.; Çakir, D.; Sevik, C.; Peeters, F.M. |
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Title |
Piezoelectricity in two-dimensional materials : comparative study between lattice dynamics and ab initio calculations |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
95 |
Issue |
95 |
Pages |
125415 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The elastic constant C-11 and piezoelectric stress constant e(1),(11) of two-dimensional (2D) dielectric materials comprising h-BN, 2H-MoS2, and other transition-metal dichalcogenides and dioxides are calculated using lattice dynamical theory. The results are compared with corresponding quantities obtained with ab initio calculations. We identify the difference between clamped-ion and relaxed-ion contributions with the dependence on inner strains which are due to the relative displacements of the ions in the unit cell. Lattice dynamics allows us to express the inner-strain contributions in terms of microscopic quantities such as effective ionic charges and optoacoustical couplings, which allows us to clarify differences in the piezoelectric behavior between h-BN and MoS2. Trends in the different microscopic quantities as functions of atomic composition are discussed. |
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Thesis |
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Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
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Language |
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Wos |
000396013400005 |
Publication Date |
2017-03-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
29 |
Open Access |
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Notes |
; The authors acknowledge useful discussions with L. Wirtz and A. Molina-Sanchez. This work was supported by the Methusalem program and the Fonds voor Wetenschappelijk Onderzoek-Vlaanderen. Computational resources were provided by HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:142444 |
Serial |
4603 |
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Permanent link to this record |
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Author |
Michel, K.H.; Scuracchio, P.; Peeters, F.M. |
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Title |
Sound waves and flexural mode dynamics in two-dimensional crystals |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
96 |
Issue |
9 |
Pages |
094302 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Starting from a Hamiltonian with anharmonic coupling between in-plane acoustic displacements and outof-plane (flexural) modes, we derived coupled equations of motion for in-plane displacements correlations and flexural mode density fluctuations. Linear response theory and time-dependent thermal Green's functions techniques are applied in order to obtain different response functions. As external perturbations we allow for stresses and thermal heat sources. The displacement correlations are described by a Dyson equation where the flexural density distribution enters as an additional perturbation. The flexural density distribution satisfies a kinetic equation where the in-plane lattice displacements act as a perturbation. In the hydrodynamic limit this system of coupled equations is at the basis of a unified description of elastic and thermal phenomena, such as isothermal versus adiabatic sound motion and thermal conductivity versus second sound. The general theory is formulated in view of application to graphene, two-dimensional h-BN, and 2H-transition metal dichalcogenides and oxides. |
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Thesis |
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Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
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Language |
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Wos |
000409246200003 |
Publication Date |
2017-09-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
6 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem program. ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:145630 |
Serial |
4751 |
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Permanent link to this record |
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Author |
Scuracchio, P.; Michel, K.H.; Peeters, F.M. |
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Title |
Phonon hydrodynamics, thermal conductivity, and second sound in two-dimensional crystals |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
99 |
Issue |
14 |
Pages |
144303 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Starting from our previous work in which we obtained a system of coupled integrodifferential equations for acoustic sound waves and phonon density fluctuations in two-dimensional (2D) crystals, we derive here the corresponding hydrodynamic equations, and we study their consequences as a function of temperature and frequency. These phenomena encompass propagation and damping of acoustic sound waves, diffusive heat conduction, second sound, and Poiseuille heat flow, all of which are characterized by specific transport coefficients. We calculate these coefficients by means of correlation functions without using the concept of relaxation time. Numerical calculations are performed as well in order to show the temperature dependence of the transport coefficients and of the thermal conductivity. As a consequence of thermal tension, mechanical and thermal phenomena are coupled. We calculate the dynamic susceptibilities for displacement and temperature fluctuations and study their resonances. Due to the thermomechanical coupling, the thermal resonances such as the Landau-Placzek peak and the second-sound doublet appear in the displacement susceptibility, and conversely the acoustic sound wave doublet appears in the temperature susceptibility, Our analytical results not only apply to graphene, but they are also valid for arbitrary 2D crystals with hexagonal symmetry, such as 2D hexagonal boron nitride, 2H-transition-metal dichalcogenides, and oxides. |
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Wos |
000464717300006 |
Publication Date |
2019-04-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
16 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ admin @ c:irua:159346 |
Serial |
5225 |
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Permanent link to this record |
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Author |
Michel, K.H.; Copley, J.R.D. |
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Title |
Orientational mode coupling, diffuse scattering, and the order-disorder phase transition in solid C60 |
Type |
A3 Journal article |
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Year |
1997 |
Publication |
Zeitschrift für Physik: B: condensed matter and quanta |
Abbreviated Journal |
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Volume |
103 |
Issue |
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Pages |
369-376 |
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Keywords |
A3 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Berlin |
Editor |
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Language |
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Wos |
A1997XL52100005 |
Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0340-224x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
21 |
Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:21181 |
Serial |
2517 |
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Permanent link to this record |
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Author |
Nikolaev, A.V.; Prassides, K.; Michel, K.H. |
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Title |
Phase transitions in AC60 (A=Rb, Cs) fullerides |
Type |
A3 Journal article |
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Year |
1997 |
Publication |
Recent advances in the chemistry and physics of fullerenes and related materials |
Abbreviated Journal |
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Volume |
5 |
Issue |
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Pages |
450-460 |
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Keywords |
A3 Journal article; Condensed Matter Theory (CMT) |
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Corporate Author |
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Publisher |
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Place of Publication |
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Wos |
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Publication Date |
0000-00-00 |
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Series Editor |
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Series Issue |
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Edition |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:21182 |
Serial |
2596 |
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Permanent link to this record |
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Author |
Lamoen, D.; Michel, K.H. |
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Title |
Molecular structure, crystal field and orientational order in solid C60 |
Type |
H1 Book chapter |
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Year |
1994 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
183-202 |
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Keywords |
H1 Book chapter; Condensed Matter Theory (CMT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
s.l. |
Editor |
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Language |
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Wos |
A1994BE86T00011 |
Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
0-7923-3109-5 |
Additional Links |
UA library record; WoS full record; |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
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Call Number |
UA @ lucian @ c:irua:9355 |
Serial |
2186 |
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Permanent link to this record |
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Author |
Michel, K.H.; Nikolaev, A.V.; Verberck, B. |
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Title |
Theory of crystal structures of polymerized C60-fullerite and fullerides AC60, A=K, Rb, Cs |
Type |
H1 Book chapter |
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Year |
2001 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
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Keywords |
H1 Book chapter; Condensed Matter Theory (CMT) |
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Place of Publication |
s.l. |
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Wos |
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Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
462-465 |
Series Issue |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record; WoS full record; |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:36883 |
Serial |
3614 |
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Permanent link to this record |
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Author |
Michel, K.H.; Copley, J.R.D. |
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Title |
Orientation fluctuations, diffuse scattering and orientational order in solid C60 |
Type |
H3 Book chapter |
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Year |
1996 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
381-384 |
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Keywords |
H3 Book chapter; Condensed Matter Theory (CMT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
World Scientific |
Place of Publication |
Singapore |
Editor |
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Language |
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Wos |
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Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
COMPUTER SCIENCE, INTERDISCIPLINARY 11/104 Q1 # PHYSICS, MATHEMATICAL 1/53 Q1 # |
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Call Number |
UA @ lucian @ c:irua:16358 |
Serial |
2512 |
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Permanent link to this record |
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Author |
Nikolaev, A.V.; Michel, K.H.; Copley, J.R.D. |
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Title |
Orientational disorder and order in C60-fullerite and in MC60-alkali metal fullerides |
Type |
H3 Book chapter |
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Year |
1999 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
183-214 |
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Keywords |
H3 Book chapter; Condensed Matter Theory (CMT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
Plenum Press |
Place of Publication |
New York |
Editor |
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Language |
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Wos |
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Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:28505 |
Serial |
2515 |
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Permanent link to this record |
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Author |
Nikolaev, A.V.; Michel, K.H. |
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Title |
Ab initio approach to superexchange interactions in alkali doped fullerides AC60 |
Type |
P1 Proceeding |
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Year |
2004 |
Publication |
AIP conference proceedings
T2 – 18th International Winterschool/Euroconference on Electronic Properties, of Novel Materials, MAR 06-JUN 13, 2004, Kirchberg, AUSTRIA |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
393-396 |
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Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
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Abstract |
The superexchange interactions between the fullerenes arise as a result of the electron transfer from the C-60 molecule to the alkali atom and back. We present a scheme, which is a configuration interaction approach based on the valence bond (Heitler-London) method. The effect of superexchange is described together with chemical bonding by constructing and solving a secular equation, rather than by using a perturbation treatment. We have considered 180degrees and 90degrees superexchange for the C-60 Cs-C-60 pathways. The calculations account for unusual electronic properties of polymer orthorhombic and quenched cubic phases of CsC60: two lines in nuclear magnetic resonance experiments, the development of a spin-singlet ground state and a decrease of magnetic susceptibility as T-->0. |
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Publisher |
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Place of Publication |
New York |
Editor |
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Language |
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Wos |
000224699400085 |
Publication Date |
2004-11-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
723 |
Series Issue |
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Edition |
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ISSN |
0-7354-0204-3 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:103752 |
Serial |
27 |
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Permanent link to this record |
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Author |
Nikolaev, A.V.; Michel, K.H. |
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Title |
Molecular terms and optical transitions of C60n+/- molecular ions |
Type |
P1 Proceeding |
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Year |
2002 |
Publication |
AIP conference proceedings
T2 – 16th International Winterschool on Electronic Properties of Novel, Materials, MAR 02-09, 2002, KIRCHBERG, AUSTRIA |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
417-420 |
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Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
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Abstract |
We have studied the molecular energy terms of the hole configurations (h(u)(+))(m), m=2,3,4,5 of C-60(m+) cations and the electronic configurations (t(1u))(n) n=2,3,4, as well as (t(1u))(n-1)t(1g) of the C-60(n-) anions. The lowest terms (within an energy span of 0.03 eV) for C-60(2+) are three triplets T-3(1g), (3)G(g), T-3(2g) and for C-60(3+) are three quartets T-4(1u), (4)G(u), T-4(2u), which favor Jahn-Teller distortions. For the ground state of C-60(2-) we find a triplet T-3(1g) in agreement with Hund's rules. Our method takes into account intramolecular direct and exchange multipolar Coulomb interactions. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York |
Editor |
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Language |
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Wos |
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Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
633 |
Series Issue |
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Edition |
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ISSN |
0-7354-0088-1 |
ISBN |
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Additional Links |
UA library record; WoS full record; |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:103905 |
Serial |
2187 |
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Permanent link to this record |
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Author |
Bussmann-Holder, A.; Michel, K.H. |
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Title |
Proton tunneling and nonlinear polarizability effects in hydrogen-bonded ferroelectrics |
Type |
P1 Proceeding |
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Year |
1998 |
Publication |
AIP conference proceedings
T2 – 5th Williamsburg Workshop on 1st-Principles Calculations for, Ferroelectrics, FEB 01-04, 1998, WILLIAMSBURG, VA |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
202-206 |
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Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
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Abstract |
Hydrogen-bonded ferroelectrics are modelled by a coupled spin/nonlinear lattice (polarizability) interaction Hamiltonian, where specifically the geometry of the hydrogen bond is included. The model leads to a structural phase transition and describes correctly the isotope effect due to the substitution H/D in hydrogen-bonded systems in terms of bond length changes. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York |
Editor |
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Language |
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Wos |
000075034000022 |
Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
436 |
Edition |
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ISSN |
1-56396-730-8 |
ISBN |
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Additional Links |
UA library record; WoS full record; |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:104344 |
Serial |
2733 |
|
Permanent link to this record |