Quasiparticle and Optical Properties of Hydrogen Titanate and Its Defective Systems: An Investigation by Density Functional Theory with Hubbard Correction, Many‐Body Perturbation Theory, and Bethe–Salpeter Equation

2019 ◽  
Vol 257 (3) ◽  
pp. 1900054 ◽  
Author(s):  
Wala Elsayed ◽  
Sahar Abdalla ◽  
Nicola Seriani
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Perturbation Theory ◽  
Density Functional ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory ◽  
Hydrogen Titanate

exciting: a full-potential all-electron package implementing density-functional theory and many-body perturbation theory

2014 ◽  
Vol 26 (36) ◽  
pp. 363202 ◽  
Author(s):  
Andris Gulans ◽  
Stefan Kontur ◽  
Christian Meisenbichler ◽  
Dmitrii Nabok ◽  
Pasquale Pavone ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Perturbation Theory ◽  
Density Functional ◽  
Full Potential ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

scholarly journals Optical and Electronic Properties of Organic NIR-II Fluorophores by Time-Dependent Density Functional Theory and Many-Body Perturbation Theory: GW-BSE Approaches

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2293
Author(s):  
Nguyet N. T. Pham ◽  
Seong Hun Han ◽  
Jong S. Park ◽  
Seung Geol Lee
Keyword(s):  
Density Functional Theory ◽  
Perturbation Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Time Dependent ◽  
Many Body ◽  
Functional Theory ◽  
Optical And Electronic Properties ◽  
Many Body Perturbation Theory ◽  
Dependent Density

Organic-molecule fluorophores with emission wavelengths in the second near-infrared window (NIR-II, 1000–1700 nm) have attracted substantial attention in the life sciences and in biomedical applications because of their excellent resolution and sensitivity. However, adequate theoretical levels to provide efficient and accurate estimations of the optical and electronic properties of organic NIR-II fluorophores are lacking. The standard approach for these calculations has been time-dependent density functional theory (TDDFT). However, the size and large excitonic energies of these compounds pose challenges with respect to computational cost and time. In this study, we used the GW approximation combined with the Bethe-Salpeter equation (GW-BSE) implemented in many-body perturbation theory approaches based on density functional theory. This method was used to perform calculations of the excited states of two NIR molecular fluorophores (BTC980 and BTC1070), going beyond TDDFT. In this study, the optical absorption spectra and frontier molecular orbitals of these compounds were compared using TDDFT and GW-BSE calculations. The GW-BSE estimates showed excellent agreement with previously reported experimental results.

scholarly journals Introductory lecture: when the density of the noninteracting reference system is not the density of the physical system in density functional theory

2020 ◽  
Vol 224 ◽  
pp. 9-26
Author(s):  
Ye Jin ◽  
Neil Qiang Su ◽  
Zehua Chen ◽  
Weitao Yang
Keyword(s):  
Density Functional Theory ◽  
Perturbation Theory ◽  
Physical System ◽  
Reference System ◽  
Linear Response ◽  
Density Functional ◽  
Many Body ◽  
Functional Theory ◽  
Introductory Lecture ◽  
Many Body Perturbation Theory

We develop expressions for electron density defined through the linear response for general density functional approximations, demonstrating results for orbital functionals and for many-body perturbation theory, and explore the connections to developments in DFT.

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