Time-resolved photoabsorption in finite systems: A first-principles NEGF approach

We describe a first-principles NonEquilibrium Green's Function (NEGF) approach to time-resolved photoabsortion spectroscopy in atomic and nanoscale systems. The method is used to highlight a recently discovered dynamical correlation effect in the spectrum of a Krypton gas subject to a strong io...

Full description

Saved in:
Bibliographic Details
Published in:Journal of physics. Conference series 2016-03, Vol.696 (1), p.12004
Main Authors: Perfetto, E., Uimonen, A.-M., van Leeuwen, R., Stefanucci, G.
Format: Article
Language:English
Subjects:
Approximation
Density functional theory
First principles
Green's functions
Krypton
Mathematical analysis
Photoabsorption
Physics
Spectrum analysis
Time dependence
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We describe a first-principles NonEquilibrium Green's Function (NEGF) approach to time-resolved photoabsortion spectroscopy in atomic and nanoscale systems. The method is used to highlight a recently discovered dynamical correlation effect in the spectrum of a Krypton gas subject to a strong ionizing pump pulse. We propose a minimal model that captures the effect, and study the performance of time-local approximations versus time-nonlocal ones. In particular we implement the time-local Hartree-Fock and Markovian second Born (2B) approximation as well as the exact adiabatic approximation within the Time-Dependent Density Functional Theory framework. For the time-nonlocal approximation we instead use the 2B one. We provide enough convincing evidence for the fact that a proper description of the spectrum of an evolving admixture of ionizing atoms requires the simultaneous occurrence of correlation and memory effects.
ISSN:1742-6588
1742-6596
DOI:10.1088/1742-6596/696/1/012004