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Application Of The Linear Muffin-Tin-Orbital Band-Structure Method To Calculate Optical Properties Of Solids, R. Zemach, J. Ashkenazi, E. Ehrenfreund Jan 1989

Application Of The Linear Muffin-Tin-Orbital Band-Structure Method To Calculate Optical Properties Of Solids, R. Zemach, J. Ashkenazi, E. Ehrenfreund

Physics Articles and Papers

Optical matrix elements have been derived for crystals by applying the theory of optical transitions within the formalism of the linear muffin-tin-orbital band-structure method and using Racah algebra. A Brillouin-zone integration by the tetrahedron method allows straightforward numerical computation of the optical function ε2(ω) [or σ(ω)]. Other optical functions may be derived by using a Kramers-Kronig analysis.


Calculation Of Optical Properties Of Trans-Polyacetylene By The Linear Muffin-Tin-Orbital Method, R. Zemach, J. Ashkenazi, E. Ehrenfreund Jan 1989

Calculation Of Optical Properties Of Trans-Polyacetylene By The Linear Muffin-Tin-Orbital Method, R. Zemach, J. Ashkenazi, E. Ehrenfreund

Physics Articles and Papers

The basic optical properties of trans-(CH)x in the P21/n and the P21/a space groups are derived from first principles. The relevant optical matrix elements are calculated within the self-consistent linear muffin-tin-orbital band-structure method. The derived optical response functions are compared with the results from a variety of optical as well as electron-energy-loss experimental studies. It is shown that the measured optical constants are consistent with the P21/n structure.


Ground State Of Trans-Polyacetylene And The Peierls Mechanism - Ashkenazi Et Al. Reply, J. Ashkenazi, W. E. Pickett, H. Krakauer, C. S. Wang, B. M. Klein, S. R. Chubb Jan 1989

Ground State Of Trans-Polyacetylene And The Peierls Mechanism - Ashkenazi Et Al. Reply, J. Ashkenazi, W. E. Pickett, H. Krakauer, C. S. Wang, B. M. Klein, S. R. Chubb

Physics Articles and Papers

Ashkenazi et al. reply to Original Article: J. Ashkenazi, W. E. Pickett, H. Krakauer, C. S. Wang, B. M. Klein, and S. R. Chubb, Ground state of trans-polyacetylene and the Peierls mechanism, Physical Review Letters 62, 2016 (1989).


Ground State Of Trans-Polyacetylene And The Peierls Mechanism - Errata, J. Ashkenazi, W. E. Pickett, H. Krakauer, C. S. Wang, B. M. Klein, S. R. Chubb Jan 1989

Ground State Of Trans-Polyacetylene And The Peierls Mechanism - Errata, J. Ashkenazi, W. E. Pickett, H. Krakauer, C. S. Wang, B. M. Klein, S. R. Chubb

Physics Articles and Papers

Errata to Original Article: J. Ashkenazi, W. E. Pickett, H. Krakauer, C. S. Wang, B. M. Klein, and S. R. Chubb, Ground state of trans-polyacetylene and the Peierls mechanism, Physical Review Letters, 62, 2016 (1989).


Ground State Of Trans-Polyacetylene And The Peierls Mechanism, J. Ashkenazi, W. E. Pickett, H. Krakauer, C. S. Wang, B. M. Klein, S. R. Chubb Jan 1989

Ground State Of Trans-Polyacetylene And The Peierls Mechanism, J. Ashkenazi, W. E. Pickett, H. Krakauer, C. S. Wang, B. M. Klein, S. R. Chubb

Physics Articles and Papers

It is shown formally that the Peierls expression is inadequate for studying the instabilities of a physically realizable one-dimensional chain of atoms, due to the long-range nature of the Coulomb interaction. Detailed total-energy studies of trans-polyacetylene, for both suggested crystal structures (P21/n,P21/a) and for the one-dimensional chain, establish that no appreciable total-energy minimum occurs for nonzero dimerization amplitude within the local-density approximation. The measured dimerization is discussed within the context of recent models of electron correlation.


Excitations In A Nearly Half-Filled Hubbard Model With U=∞, S. E. Barnes Jan 1989

Excitations In A Nearly Half-Filled Hubbard Model With U=∞, S. E. Barnes

Physics Articles and Papers

It is shown that, even near half filling, the elementary excitations of the large-U Hubbard model form wide bands of width ∼t, the intersite hopping integral, and that the slave-boson-based mean-field approximation is qualitatively wrong in the relevant limit. This large-U limit has no Kondo-type divergences.