The static dielectric properties of (001)(GaAs)(p)/(AlAs)(p) superlattices have been calculated as a function of their period p for 1< or = p < or =12, starting from density-functional theory. The interplay between quantum confinement and local field effects is shown to be crucial. For light polarized in the growth direction it leads to the otherwise surprising justification of the use of a classical effective medium theory, even for the smallest periods. Only the inclusion of both contributions allows in ab initio and in semiempirical calculations to reproduce the experimentally observed birefringence.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevLett.89.216803 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Large exciton binding energy in a bulk van der Waals magnet from quasi-1D electronic localization.
Nat Commun
January 2025
Department of Physics, University of Michigan, Ann Arbor, MI, USA.
Excitons, bound electron-hole pairs, influence the optical properties in strongly interacting solid-state systems and are typically most stable and pronounced in monolayer materials. Bulk systems with large exciton binding energies, on the other hand, are rare and the mechanisms driving their stability are still relatively unexplored. Here, we report an exceptionally large exciton binding energy in single crystals of the bulk van der Waals antiferromagnet CrSBr.
View Article and Find Full Text PDFO-H/N-H bond dissociation energies in 1,4-hydroquinone, 4-hydroxydiphenylamine, N,N'-diphenyl-1,4-phenylenediamine, and their phenoxyl and aminyl radicals.
J Mol Graph Model
January 2025
Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of the Russian Academy of Sciences, 1 Academician Semenov Avenue, 142432, Chernogolovka, Russian Federation.
Gas phase bond dissociation energies (BDE) O-H/N-H in hydroquinone (HQ), 4-aminophenol (AP), 1,4-phenylenediamine (PDA), 4-hydroxydiphenylamine (HDPA), N,N'-diphenyl-1,4-phenylenediamine (DPPDA) as well as in their phenoxyl/aminyl radicals have been determined using a combined technique of quantum chemical calculation. The technique included a series of DFT (PBE1PBE, TPSSTPSS, M06-2X), ab initio (DLPNO-CCSD(T)) methods with valence 3ξ-basis sets, composite methods of Gaussian family (G4) and Weizmann theory with ab initio Brueckner Doubles (W1BD), as well as reference reactions of different levels of structural similarity. W1BD method was used in combination with isodesmic reactions for BDE estimation (kJ∙mol) of compounds with the only aromatic fragment: BDE = 352.
View Article and Find Full Text PDFMolecular dynamics simulations of functionalized hBN nanopores in water: Ab initio force field and implications for water desalination.
J Chem Phys
January 2025
Department of Chemical Engineering, Indian Institute of Science, Bengaluru, Karnataka 560012, India.
Heteropolar two-dimensional materials, including hexagonal boron nitride (hBN), are promising candidates for seawater desalination and osmotic power harvesting, but previous simulation studies have considered bare, unterminated nanopores in molecular dynamics (MD) simulations. There is presently a lack of force fields to describe functionalized nanoporous hBN in aqueous media. To address this gap, we conduct density functional theory (DFT)-based ab initio MD simulations of hBN nanopores surrounded by water molecules.
View Article and Find Full Text PDFTime-resolved vibronic spectra with nuclear-electronic orbital time-dependent configuration interaction.
J Chem Phys
January 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
Time-resolved spectroscopy is an important tool for probing photochemically induced nonequilibrium dynamics and energy transfer. Herein, a method is developed for the ab initio simulation of vibronic spectra and dynamical processes. This framework utilizes the recently developed nuclear-electronic orbital time-dependent configuration interaction (NEO-TDCI) approach, which treats all electrons and specified nuclei quantum mechanically on the same footing.
View Article and Find Full Text PDFMinimum Energy Conical Intersection Optimization Using DFT/MRCI(2).
J Chem Theory Comput
January 2025
Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5,Canada.
The combined density functional theory and multireference configuration interaction (DFT/MRCI) method is a semiempirical electronic structure approach that is both computationally efficient and has predictive accuracy for the calculation of electronic excited states and for the simulation of electronic spectroscopies. However, given that the reference space is generated via a selected-CI procedure, a challenge arises in the construction of smooth potential energy surfaces. To address this issue, we treat the local discontinuities that arise as noise within the Gaussian progress regression framework and learn the surfaces by explicitly incorporating and optimizing a white-noise kernel.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!