Density functional theory (DFT) based modeling of electronic excited states is importance for investigation the photophysical/photochemical properties and spectroscopic characterization large systems. The widely used linear response time-dependent DFT (TDDFT) approach however not effective at many types states, including (but limited to) charge-transfer doubly core-level excitations. In this pe...

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We give a perspective on simulating electronic excitation and dynamics using the real-time propagation approach to time-dependent density functional theory (RT-TDDFT) in plane-wave pseudopotential formulation. RT-TDDFT is implemented various numerical formalisms recent years, its practical application often dictates most appropriate implementation of theory. discuss developments challenges, emp...

The Kohn-Sham approach to time-dependent density-functional theory (TDDFT) can be formulated, in principle exactly, by invoking the force-balance equation for density, which leads an explicit expression exchange-correlation potential as implicit density functional. It is shown that this suggests a reformulation of TDDFT terms second time derivative rather than itself. result time-local scheme o...

Optical properties of symmetry-forbidden π-π transitions in benzene are calculated with the time-dependent density functional theory (TDDFT), using an adiabatic LDA functional. Quantities calculated are the envelopes of the Franck-Condon factors of the vibrationally promoted transitions and the associated oscillator strengths. The strengths, which span three orders of magnitude, are reproduced ...

Time-dependent density matrix functional theory can be formulated in terms of coupled-perturbed response equations, in which a coupling matrix K(omega) features, analogous to the well-known time-dependent density functional theory (TDDFT) case. An adiabatic approximation is needed to solve these equations, but the adiabatic approximation is much more critical since there is not a good "zero ord...

The optical response of a system formed by quantum emitter and plasmonic gap nanoantenna is theoretically addressed within the frameworks classical electrodynamics time-dependent density functional theory (TDDFT). A fully many-body description electron dynamics TDDFT allows for analyzing effect electronic coupling between nanoantenna, usually ignored in descriptions response. We show that hybri...

This study arises from the attempt to answer following question: how different descriptions of electronic exchange and correlation affect high-harmonic generation (HHG) spectroscopy H2, N2, CO2 molecules? We compare HHG spectra for with ab initio structure methods: real-time time-dependent configuration interaction density functional theory (RT-TDDFT) using truncated basis sets composed correla...

In the context of the density functional theory we consider the single particle ex-citation spectra of electron systems. As a result, we have related the single particle excitations with the eigenvalues of the corresponding Kohn-Sham equations. In a case when the exchange correlation functional is approximated by the exchange functional the coupling equations are very simple, while the single p...

We show that the analytic structure of dynamical exchange-correlation (xc) kernels semiconductors and insulators can be sensed in terms its poles, which mark physically relevant frequencies system where counterphase motion discrete collective excitations occurs: If excited, modes counterbalance each other, making exhibit none at all or extremely weak density response. This property employed to ...