Time-dependent density-functional calculations with asymptotically correct exchange-correlation potentials

2004 ◽  
Vol 69 (5) ◽  
Author(s):  
Igor Vasiliev ◽  
Richard M. Martin
Keyword(s):  
Density Functional Calculations ◽  
Density Functional ◽  
Time Dependent ◽  
Exchange Correlation ◽  
Dependent Density

EXCHANGE–CORRELATION KERNEL IN TIME-DEPENDENT DENSITY FUNCTIONAL THEORY DERIVED FROM MANY-BODY THEORY

2004 ◽  
Vol 18 (07) ◽  
pp. 1055-1067 ◽  
Author(s):  
K. KARLSSON ◽  
F. ARYASETIAWAN
Keyword(s):  
Density Functional Theory ◽  
Optical Absorption ◽  
Density Functional ◽  
Time Dependent ◽  
Many Body ◽  
Functional Theory ◽  
Correlation Kernel ◽  
Exchange Correlation ◽  
Many Body Theory ◽  
Dependent Density

We derive a simplified Bethe–Salpeter equation for calculating optical absorption based on the assumption of a local electron–hole interaction. The original four-point equation for the kernel is reduced to a two-point one. A connection to the exchange–correlation kernel in time-dependent density functional theory can be established. The resulting fxc is found to be -W/2 where W contains only the short-range (local) part of the Coulomb screened interaction. This simple approximation was successfully applied to optical absorption spectra of some excitonic crystals, reproducing not only the continuum excitons but also the bound ones.

scholarly journals Optical Properties of Silver-Mediated DNA from Molecular Dynamics and Time Dependent Density Functional Theory

2018 ◽  
Vol 19 (8) ◽  
pp. 2346 ◽  
Author(s):  
Esko Makkonen ◽  
Patrick Rinke ◽  
Olga Lopez-Acevedo ◽  
Xi Chen
Keyword(s):  
Molecular Dynamics ◽  
Density Functional ◽  
Time Dependent ◽  
Basis Set ◽  
Dna Nanostructures ◽  
Exchange Correlation ◽  
Hartree Fock ◽  
Spurious Peak ◽  
20 Nm ◽  
Dependent Density

We report a combined quantum mechanics/molecular mechanics (QM/MM) molecular dynamics and time-dependent density functional (TDDFT) study of metal-mediated deoxyribonucleic acid (M-DNA) nanostructures. For the Ag + -mediated guanine tetramer, we found the maug-cc-pvdz basis set to be sufficient for calculating electronic circular dichroism (ECD) spectra. Our calculations further show that the B3LYP, CAM-B3LYP, B3LYP*, and PBE exchange-correlation functionals are all able to predict negative peaks in the measured ECD spectra within a 20 nm range. However, a spurious positive peak is present in the CAM-B3LYP ECD spectra. We trace the origins of this spurious peak and find that is likely due to the sensitivity of silver atoms to the amount of Hartree–Fock exchange in the exchange-correlation functional. Our presented approach provides guidance for future computational investigations of other Ag + -mediated DNA species.

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