Basing on the earlier works on the hierarchical equations of motion for quantum transport, we present in this paper a first principles scheme for time-dependent quantum transport by combining time-dependent density functional theory (TDDFT) and Keldysh's non-equilibrium Green's function formalism. This scheme is beyond the wide band limit approximation and is directly applicable to the case of ...

We report the spin-selective optical excitation of carriers in inversion-symmetric bulk samples of the transition metal dichalcogenide (TMDC) WSe_{2}. Employing time- and angle-resolved photoelectron spectroscopy (trARPES) and complementary time-dependent density functional theory (TDDFT), we observe spin-, valley-, and layer-polarized excited state populations upon excitation with circularly p...

A practical computational scheme based on time-dependent density functional theory TDDFT and ultrasoft pseudopotentials USPP is developed to study electron dynamics in real time. A modified Crank-Nicolson time-stepping algorithm is adopted, under plane-wave basis. The scheme is validated by calculating the optical absorption spectra for a sodium dimer and a benzene molecule. As an application o...

Azobenzenes have been noted for their ability to undergo isomerization between the straight trans isomer and the bent cis isomer with visible light and UV irradiation, respectively. Their photochemically induced isomerization make them highly useful in optical switching devices. Time-dependent density functional theory (TDDFT) can model highly complex molecules like azobenzenes accurately, effi...

The electronic structure and size-scaling of optoelectronic properties in cycloparaphenylene carbon nanorings are investigated using time-dependent density functional theory (TDDFT). The TDDFT calculations on these molecular nanostructures indicate that the lowest excitation energy surprisingly becomes larger as the carbon nanoring size is increased, in contradiction with typical quantum confin...

The nature and energetics of the low-lying singlet states of polyenes have presented significant challenges for electronic structure methods. This is particularly true for conventional implementations of time-dependent density functional theory (TDDFT), which, because of their use of the adiabatic approximation, have difficulty in describing states of ‘doubly-excited character’. We show that us...

We present a technique for the iterative diagonalization of random-phase approximation (RPA) matrices, which are encountered in the framework of time-dependent density-functional theory (TDDFT) and the Bethe-Salpeter equation. The non-Hermitian character of these matrices does not permit a straightforward application of standard iterative techniques used, i.e., for the diagonalization of ground...

Time-dependent density functional theory (TDDFT) is rapidly emerging as a premier method for solving dynamical many-body problems in physics and chemistry. The mathematical foundations of TDDFT are established through the formal existence of a fictitious non-interacting system (known as the Kohn–Sham system), which can reproduce the one-electron reduced probability density of the actual system....

We develop an approach for dynamical (ω > 0) embedding of mixed quantum mechanical (QM)/classical (or more precisely QM/electrodynamics) systems with a quantum sub-region, described by time-dependent density functional theory (TDDFT), within a classical sub-region, modeled here by the recently proposed near-field (NF) method. Both sub-systems are propagated simultaneously and are coupled throug...

Over 35 years ago, the low-lying bands in the absorption spectra of metal hexacarbonyls were assigned to ligand-field (LF) excitations. Recent time-dependent density functional theory (TDDFT) calculations on M(CO)6 (M = Cr, Mo, W) are not in accord with this interpretation. Here we extend TDDFT calculations to the isoelectronic series V(CO)6-, Cr(CO)6, and Mn(CO)6+. By analyzing the trends in t...