Kohn-Sham equations for multicomponent systems: The exchange and correlation energy functional

1998 ◽  
Vol 57 (4) ◽  
pp. 2146-2152 ◽  
Author(s):  
Nikitas Gidopoulos
Keyword(s):  
Correlation Energy ◽  
Energy Functional ◽  
Multicomponent Systems ◽  
Exchange And Correlation

A Combination of the Work Formalism for Exchange with an Optimized Correlation Energy Functional for Atoms

1995 ◽  
Vol 5 (9) ◽  
pp. 1277-1287 ◽  
Author(s):  
N. A. Cordero ◽  
K. D. Sen ◽  
J. A. Alonso ◽  
L. C. Balbás
Keyword(s):  
Correlation Energy ◽  
Energy Functional

scholarly journals Quantum Calculations on Ion Channels: Why Are They More Useful Than Classical Calculations, and for Which Processes Are They Essential?

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 655
Author(s):  
Alisher M. Kariev ◽  
Michael E. Green
Keyword(s):  
Charge Transfer ◽  
Ion Channels ◽  
Correlation Energy ◽  
Force Fields ◽  
Critical Role ◽  
Atomic Scale ◽  
Quantum Calculations ◽  
Interatomic Distances ◽  
Classical Analogue ◽  
Exchange And Correlation

There are reasons to consider quantum calculations to be necessary for ion channels, for two types of reasons. The calculations must account for charge transfer, and the possible switching of hydrogen bonds, which are very difficult with classical force fields. Without understanding charge transfer and hydrogen bonding in detail, the channel cannot be understood. Thus, although classical approximations to the correct force fields are possible, they are unable to reproduce at least some details of the behavior of a system that has atomic scale. However, there is a second class of effects that is essentially quantum mechanical. There are two types of such phenomena: exchange and correlation energies, which have no classical analogues, and tunneling. Tunneling, an intrinsically quantum phenomenon, may well play a critical role in initiating a proton cascade critical to gating. As there is no classical analogue of tunneling, this cannot be approximated classically. Finally, there are energy terms, exchange and correlation energy, whose values can be approximated classically, but these approximations must be subsumed within classical terms, and as a result, will not have the correct dependence on interatomic distances. Charge transfer, and tunneling, require quantum calculations for ion channels. Some results of quantum calculations are shown.

Relativistic exchange-correlation energy functional: Gauge dependence of the no-pair correlation energy

1998 ◽  
Vol 58 (2) ◽  
pp. 993-1000 ◽  
Author(s):  
A. Facco Bonetti ◽  
E. Engel ◽  
R. M. Dreizler ◽  
I. Andrejkovics ◽  
H. Müller
Keyword(s):  
Correlation Energy ◽  
Pair Correlation ◽  
Energy Functional ◽  
Exchange Correlation ◽  
Gauge Dependence
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