Related papers: Large-scale first principles configuration interac…
A microscopic description of nuclei is important to understand the nuclear shell-model from fundamental principles. This is difficult to achieve for more than the lightest nuclei without an effective approximation scheme. The purpose of…
A systematic method to account for electron correlation in periodic systems which can predict quantitatively correct band structures of non-conducting solids from first principles is presented. Using localized Hartree-Fock orbitals (both…
The ability to control and modify infrared excitations in condensed matter is of both fundamental and application interests. Here we explore a system supporting low-energy excitations, in particular, mid-infrared localized plasmon modes and…
Some properties of small and medium sodium clusters are described within the RPA approach using a projected spherical single particle basis. The oscillator strengths calculated with a Schiff-like dipole transition operator and folded with…
The photoabsorption spectra of calcium-doped argon clusters CaAr_n are investigated at thermal equilibrium using a variety of theoretical and numerical tools. The influence of temperature on the absorption spectra is estimated using the…
Optical transitions in a semiconductor quantum dot are theoretically investigated, with emphasis on the coupling to longitudinal optical phonons, and including excitonic effects. When limiting to a finite number of $m$ electron and $n$ hole…
Collisionless absorption of laser energy by an electron via laser-cluster interaction in an ambient magnetic field ($B_0$) has recently renewed interest. %due to high levels of absorption. Previously, using a rigid sphere model (RSM) and an…
In this paper, we report theoretical calculations of the photo-induced absorption (PA) spectrum of naphthalene and anthracene, with the aim of understanding those excited states, which are invisible in the linear optical absorption. The…
Embedded Si and Ge nanocrystals (NCs) in wide band-gap matrices are studied theoretically using an atomistic pseudopotential approach. From small clusters to large NCs containing on the order of several thousand atoms are considered.…
Excited-state methods within the nuclear--electronic orbital (NEO) framework have the potential to capture vibrational, electronic, and vibronic transitions in a single calculation. In the NEO approach, specified nuclei, typically protons,…
A new state specific correlation correction to configuration interaction singles (CIS) excitation energies is preseted using coupled cluster perturbation theory (CCPT). General expressions for CIS-CCPT are derived and expanded explicitly to…
Optically detected magnetic resonance (ODMR) is an efficient and reliable method that enables initialization and readout of spin states through spin-photon interface. In general, high quantum efficiency and large spin-dependent…
The surface modes of a composite consisting of aligned metallic wires with square cross sections are investigated, on the basis of photonic band structure calculations. The effective long-wavelength dielectric response function is computed,…
We present the positron coupled cluster singles and doubles (POS-CCSD) method to calculate positron binding energies in molecules. This framework treats electrons and positrons on an equal footing and includes up to simultaneous…
The question whether the linear absorption spectra of metal clusters can be interpreted as density oscillations (collective ``plasmons'') or can only be understood as transitions between distinct molecular states is still a matter of debate…
Applying a variational multiparticle-multihole configuration mixing method whose purpose is to include correlations beyond the mean field in a unified way without particle number and Pauli principle violations, we investigate pairing-like…
We present a detailed theoretical characterization of the two fundamental collective resonances underlying the xenon giant dipole resonance (GDR). This is achieved consistently by two complementary methods implemented within the framework…
An ab initio density functional study was performed investigating the adsorption of CO$_2$ on the neutral boron B$_{n}$ ($n = 10-13$) clusters, characterized by planar and quasiplanar ground-state atomic structures. For all four clusters,…
An externally corrected coupled cluster (CC) method, where an adaptive configuration interaction (ACI) wave function provides the external cluster amplitudes, named ACI-CC, is presented. By exploiting the connection between configuration…
We study the effects of higher-order electronic correlations in the systems with particle-hole excited states using a relativistic hybrid method that combines configuration interaction and linearized coupled-cluster approaches. We find the…