Browsing FAS Scholarly Articles by Keyword "density functional theory"
Now showing items 1-10 of 10
-
Dumbbell Defects in FeSe Films: A Scanning Tunneling Microscopy and First-Principles Investigation
(American Chemical Society (ACS), 2016)The properties of iron-based superconductors (Fe-SCs) can be varied dramatically with the introduction of dopants and atomic defects. As a pressing example, FeSe, parent phase of the highest-Tc Fe-SC, exhibits prevalent ... -
Electronic Structure Calculations in Arbitrary Electrostatic Environment
(American Institute of Physics, 2012)Modeling of electronic structure of molecules in electrostatic environments is of considerable relevance for surface-enhanced spectroscopy and molecular electronics. We have developed and implemented a novel approach to ... -
Exciton Coherence Lifetimes from Electronic Structure
(American Institute of Physics, 2012-04-06)We model the coherent energy transfer of an electronic excitation within covalently linked aromatic homodimers from first-principles. Our results shed light on whether commonly used models of the bath calculated via detailed ... -
Exciton Transport in Thin-Film Cyanine Dye J-Aggregates
(American Institute of Physics, 2012)We present a theoretical model for the study of exciton dynamics in J-aggregated monolayers of fluorescent dyes. The excitonic evolution is described by a Monte-Carlo wave function approach which allows for a unified ... -
Failure of Conventional Density Functionals for the Prediction of Molecular Crystal Polymorphism: A Quantum Monte Carlo Study
(American Chemical Society (ACS), 2010)We have applied the diffusion Monte Carlo method, for the first time, to an organic molecular crystal (para-diiodobenzene) in order to determine the relative stability of its two well-known polymorphs. The DMC result ... -
First Principles Semiclassical Calculations of Vibrational Eigenfunctions
(American Institute of Physics, 2011)Vibrational eigenfunctions are calculated on-the-fly using semiclassical methods in conjunction with ab initio density functional theory classical trajectories. Various semiclassical approximations based on the time-dependent ... -
Force-field functor theory: classical force-fields which reproduce equilibrium quantum distributions
(Frontiers Media S.A., 2013)Feynman and Hibbs were the first to variationally determine an effective potential whose associated classical canonical ensemble approximates the exact quantum partition function. We examine the existence of a map between ... -
Path Integral Monte Carlo with Importance Sampling for Excitons Interacting with an Arbitrary Phonon Bath
(American Institute of Physics, 2012)The reduced density matrix of excitons coupled to a phonon bath at a finite temperature is studied using the path integral Monte Carlo method. Appropriate choices of estimators and importance sampling schemes are crucial ... -
Simplified Sum-Over-States Approach for Predicting Resonance Raman Spectra. Application to Nucleic Acid Bases
(American Chemical Society, 2011)Resonance Raman spectra provide a valuable probe into molecular excited-state structures and properties. Moreover, resonance enhancement is of importance for the chemical contribution to surface-enhanced Raman scattering. ... -
Time-Dependent Density Functional Theory of Open Quantum Systems in the Linear-Response Regime
(American Institute of Physics, 2011)Time-dependent density functional theory (TDDFT) has recently been extended to describe many-body open quantum systems evolving under nonunitary dynamics according to a quantum master equation. In the master equation ...