Accurate Theoretical Description of the 1La and 1Lb Excited States in Acenes Using the All Order Constricted Variational Density Functional Theory Method and the Local Density Approximation

2012 ◽  
Vol 8 (11) ◽  
pp. 4434-4440 ◽  
Author(s):  
Mykhaylo Krykunov ◽  
Stefan Grimme ◽  
Tom Ziegler
Keyword(s):  
Density Functional Theory ◽  
Excited States ◽  
Local Density Approximation ◽  
Density Functional ◽  
Local Density ◽  
Density Functional Theory Method ◽  
Theoretical Description ◽  
Theory Method ◽  
Density Approximation ◽  
Functional Theory

Study of Thermodynamic Properties of Superhard w-BC2N

2013 ◽  
Vol 750-752 ◽  
pp. 1141-1145
Author(s):  
Ai Ling Ding ◽  
Feng Li ◽  
Chun Mei Li ◽  
Jing Ao ◽  
Zhi Qian Chen
Keyword(s):  
Density Functional Theory ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Density Functional ◽  
Local Density ◽  
Density Functional Theory Method ◽  
Debye Model ◽  
Theory Method ◽  
Density Approximation ◽  
Functional Theory

We investigate the thermodynamic properties of superhard w-BC2N by using ab initio plane-wave pseudopotential density functional theory method within local density approximation (LDA). Through the quasi-harmonic Debye model, we investigate the thermodynamic properties of w-BC2N. The variation of the thermal expansion, the heat capacity and the Gruneisen parameter γ with pressure P and temperature T, and many other thermodynamic parameters of w-BC2N are obtained systematically.

ELECTRONIC AND DYNAMICAL PROPERTIES OF MgB2 AND RELATED COMPOUNDS

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1563-1569 ◽  
Author(s):  
G. PROFETA ◽  
A. CONTINENZA ◽  
F. BERNARDINI ◽  
G. SATTA ◽  
S. MASSIDDA
Keyword(s):  
Density Functional Theory ◽  
Local Density Approximation ◽  
Density Functional ◽  
Local Density ◽  
Density Approximation ◽  
Superconducting Properties ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Dynamical Properties ◽  
Related Compounds

We report a detailed study of the electronic and dynamical properties of MgB2 , BeB2 and of the AlMgB4 superlattice, within the local density approximation to the density functional theory. On the basis of our results we discuss the superconducting properties of these systems, and point to the high T c in MgB2 as a fortunate combination of events.

THE PROBLEM OF THE BAND GAP IN LDA CALCULATIONS

2007 ◽  
Vol 14 (03) ◽  
pp. 481-487 ◽  
Author(s):  
I. N. YAKOVKIN ◽  
P. A. DOWBEN
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Band Gap ◽  
Local Density Approximation ◽  
Density Functional ◽  
Local Density ◽  
Fine Tuning ◽  
Density Approximation ◽  
Functional Theory ◽  
Basic Physics

In calculating band structure, the local density approximation and density functional theory are widely popular and do reproduce a lot of the basic physics. Regrettably, without some fine tuning, the local density approximation and density functional theory do not generally get the details of the experimental band structure correct, in particular the band gap in semiconductors and insulators is generally found to be too small when compared with experiment. For experimentalists using commercial packages to calculate the electronic structure of materials, some caution is indicated, as some long-standing problems exist with the local density approximation and density functional theory.

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