scholarly journals Singlet and triplet excitons and charge polarons in cycloparaphenylenes: a density functional theory study

2015 ◽  
Vol 17 (22) ◽  
pp. 14613-14622 ◽  
Author(s):  
Jin Liu ◽  
Lyudmyla Adamska ◽  
Stephen K. Doorn ◽  
Sergei Tretiak
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Spatial Localization ◽  
Molecular Geometry ◽  
Density Functional Theory Study ◽  
Phonon Coupling ◽  
Functional Theory ◽  
Electron Phonon Coupling ◽  
Electronic Wavefunction ◽  
Triplet Excitons

Upon excitation, electron–phonon coupling leads to spatial localization of the electronic wavefunction and distortion of molecular geometry.

Superconductivity of lithium-doped hydrogen under high pressure

2014 ◽  
Vol 70 (2) ◽  
pp. 104-111 ◽  
Author(s):  
Yu Xie ◽  
Quan Li ◽  
Artem R. Oganov ◽  
Hui Wang
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Fermi Level ◽  
Density Of States ◽  
Lattice Dynamics ◽  
Density Functional ◽  
Phonon Coupling ◽  
Critical Temperatures ◽  
Functional Theory ◽  
Electron Phonon Coupling

The high-pressure lattice dynamics and superconductivity of newly proposed lithium hydrides (LiH2, LiH6and LiH8) have been extensively studied using density functional theory. The application of the Allen–Dynes modified McMillan equation and electron–phonon coupling calculations show that LiH6and LiH8are superconductors with critical temperatures (Tc) of 38 K at 150 GPa for LiH6and 31 K at 100 GPa for LiH8, while LiH2is not a superconductor. TheTcof LiH6increases rapidly with pressure and reaches 82 K at 300 GPa due to enhancement of the electron–phonon coupling and the increased density of states at the Fermi level, while theTcof LiH8remains almost constant.

scholarly journals Electronic and Lattice Dynamical Properties of the Iron-Based Superconductors LiFeAs and NaFeAs

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
R. A. Jishi ◽  
H. M. Alyahyaei
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Superconducting Transition ◽  
Phonon Coupling ◽  
Functional Theory ◽  
Iron Based Superconductors ◽  
Electron Phonon Coupling ◽  
Dynamical Properties ◽  
Iron Based ◽  
Conventional Type

The electronic structure and lattice vibrational frequencies of the newly discovered superconductors, LiFeAs and NaFeAs, are calculated within density functional theory. We show that, in the vicinity of the Fermi energy, the density of states is dominated by contributions from Fe 3d states. We also calculate the electron-phonon coupling strength and show that it is too weak to account for the observed values of the superconducting transition temperatures. This seems to indicate that the iron-based superconductors are not of the conventional type.

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