Related papers: Optical excitations in organic molecules, clusters…
We calculate the electronic and optical excitations of polythiophene using the GW approximation for the electronic self-energy, and include excitonic effects by solving the electron-hole Bethe-Salpeter equation. Two different situations are…
We present an alternative methodology for calculating the quasi-particle energy, energy loss, and optical spectra of a molecule deposited on graphene or a metallic substrate. To test the accuracy of the method it is first applied to the…
We present a molecular extension of our recently proposed Green's function embedding method, interacting-bath dynamical embedding theory (ibDET), for computing charged excitation energies at the $GW$ and EOM-CCSD levels. Starting from…
Excitonic effects in optical spectra and electron-hole pair excitations are described by solutions of the Bethe-Salpeter equation (BSE) that accounts for the Coulomb interaction of excited electron-hole pairs. Although for the computation…
An approach is presented which allows a self-consistent description of the fragmentation of single-particle strength for nucleons in finite nuclei employing the Greens function formalism. The self-energy to be considered in the Dyson…
The Bethe-Salpeter equation (BSE) formalism is steadily asserting itself as a new efficient and accurate tool in the ensemble of computational methods available to chemists in order to predict optical excitations in molecular systems. In…
We present a revision of predictions for nuclear shadowing in deep-inelastic scattering at small Bjorken $x_{Bj}$ corresponding to kinematic regions accessible by the future experiments at electron-ion colliders. The nuclear shadowing is…
We report on simulations and measurements of the optical absorption of silicon nanowires (NWs) versus their diameter. We first address the simulation of the optical absorption based on two different theoretical methods : the first one,…
We put forward a first-principle NonEquilibrium Green's Function (NEGF) approach to calculate the transient photoabsorption spectrum of optically thin samples. The method can deal with pump fields of arbitrary strength, frequency and…
The lowest electronic excitations of benzene and a set of donor-acceptor molecular complexes are calculated for the gas phase and on the Al(111) surface using the many-body Bethe-Salpeter equation (BSE). The energy of the charge-transfer…
We develop a method to construct a microscopic optical potential from chiral interactions for nucleon-nucleus scattering. The optical potential is constructed by combining the Green's function approach with the coupled-cluster method. To…
Solving the Bethe-Salpeter equation (BSE) for the optical polarization functions is a first principles means to model optical properties of materials including excitonic effects. One almost ubiquitously used approximation neglects the…
The optical response functions and band structures of LiCoO$_2$ are studied at different levels of approximation, from density functional theory (DFT) in the generalized gradient approximation (GGA) to quasiparticle self-consistent QS$GW$…
We study the optical absorption spectra of small Ag_n (n=2,4,6,8) clusters using the Bethe-Salpeter equation (BSE) formalism with a Hamiltonian built from GW quasiparticle energies. Calculations are based on an effective core potential…
An ensemble Green's function formalism, based on the von Neumann density matrix approach, to calculate one-electron excitation spectra of a many-electron system with degenerate ground states is proposed. A set of iterative equations for the…
We present first-principles calculations of many-electron effects on the optical response of graphene, bilayer graphene, and graphite employing the GW-Bethe Salpeter equation approach. We find that resonant excitons are formed in these…
During the past half century, a major approximation was natural in the field of light-matter interaction: the point-dipole model. It was assumed that the wavelength is much larger than the size of the emitting atom or molecule, so that the…
Despite recent advances, systematic quantitative treatment of the electron correlation problem in extended systems remains a formidable task. Systematically improvable Green's function methods capable of quantitatively describing weak and…
Using the simple (symmetric) Hubbard dimer, we analyze some important features of the $GW$ approximation. We show that the problem of the existence of multiple quasiparticle solutions in the (perturbative) one-shot $GW$ method and its…
We present an accurate approach to compute X-ray photoelectron spectra based on the $GW$ Green's function method, that overcomes shortcomings of common density functional theory approaches. $GW$ has become a popular tool to compute valence…