First-principles studies of FeS2using many-body perturbation theory in theG0W0approximation

2013 ◽  
Vol 88 (23) ◽  
Author(s):  
Timo Schena ◽  
Gustav Bihlmayer ◽  
Stefan Blügel
Keyword(s):  
Perturbation Theory ◽  
First Principles ◽  
Many Body ◽  
Many Body Perturbation Theory

scholarly journals Electron–phonon scattering and excitonic effects in T-carbon

RSC Advances ◽  
2020 ◽  
Vol 10 (41) ◽  
pp. 24515-24520 ◽  
Author(s):  
Xiangtian Bu ◽  
Shudong Wang
Keyword(s):  
Optical Properties ◽  
Perturbation Theory ◽  
First Principles ◽  
Phonon Scattering ◽  
First Principles Calculations ◽  
Many Body ◽  
Many Body Perturbation Theory ◽  
Excitonic Effects ◽  
Electron Phonon Scattering

Through first-principles calculations combining many-body perturbation theory, we investigate electron–phonon scattering and optical properties including the excitonic effects of T-carbon.

Assessing the Role of Inter-Molecular Interactions in a Perylene-Based Nanowire Using First-Principles Many-Body Perturbation Theory

2019 ◽  
Author(s):  
Tianlun Huang ◽  
D. Kirk Lewis ◽  
Sahar Sharifzadeh
Keyword(s):  
Perturbation Theory ◽  
Optical Absorption ◽  
First Principles ◽  
Room Temperature ◽  
Optoelectronic Properties ◽  
High Electron ◽  
Many Body ◽  
Molecular Electronic ◽  
Many Body Perturbation Theory

<div> <div> <div> <div> <p>We present a first-principles many-body perturbation theory study of the role of inter-molecular coupling on the optoelectronic properties of a one-dimensional p-stacked nanowire composed of perylene-3,4,9,10-tetracarboxylic diimide (PTCDI) molecules on a DNA-like backbone. We determine that strong inter-molecular electronic coupling results in large bandwidths and low carrier effective masses, suggesting a high electron mobility material. Additionally, by including the role of finite temperature phonons on optical absorption via a newly presented approach, we predict that the optical absorption spectrum at room temperature is significantly altered from room temperature due to allowed indirect transitions, while the exciton delocalization and binding energy, a measure of inter-molecular electronic interactions, remains constant. Overall, our studies indicate that strong inter-molecular coupling can dominate the optoelectronic properties of π-conjugated 1D systems even at room temperature.</p> </div> </div> </div> </div>

Assessing the Role of Inter-Molecular Interactions in a Perylene-Based Nanowire Using First-Principles Many-Body Perturbation Theory

2019 ◽  
Author(s):  
Tianlun Huang ◽  
D. Kirk Lewis ◽  
Sahar Sharifzadeh
Keyword(s):  
Perturbation Theory ◽  
Optical Absorption ◽  
First Principles ◽  
Room Temperature ◽  
Optoelectronic Properties ◽  
High Electron ◽  
Many Body ◽  
Molecular Electronic ◽  
Many Body Perturbation Theory

<div> <div> <div> <div> <p>We present a first-principles many-body perturbation theory study of the role of inter-molecular coupling on the optoelectronic properties of a one-dimensional p-stacked nanowire composed of perylene-3,4,9,10-tetracarboxylic diimide (PTCDI) molecules on a DNA-like backbone. We determine that strong inter-molecular electronic coupling results in large bandwidths and low carrier effective masses, suggesting a high electron mobility material. Additionally, by including the role of finite temperature phonons on optical absorption via a newly presented approach, we predict that the optical absorption spectrum at room temperature is significantly altered from room temperature due to allowed indirect transitions, while the exciton delocalization and binding energy, a measure of inter-molecular electronic interactions, remains constant. Overall, our studies indicate that strong inter-molecular coupling can dominate the optoelectronic properties of π-conjugated 1D systems even at room temperature.</p> </div> </div> </div> </div>

Divergence of Many-Body Perturbation Theory for Noncovalent Interactions of Large Molecules

2019 ◽  
Author(s):  
Brian Nguyen ◽  
Guo P Chen ◽  
Matthew M. Agee ◽  
Asbjörn M. Burow ◽  
Matthew Tang ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
System Size ◽  
State Density ◽  
Second Order ◽  
Binding Energies ◽  
Basis Set ◽  
Many Body ◽  
Many Body Perturbation Theory ◽  
Relative Errors ◽  
Ground State Density

Prompted by recent reports of large errors in noncovalent interaction (NI) energies obtained from many-body perturbation theory (MBPT), we compare the performance of second-order Møller–Plesset MBPT (MP2), spin-scaled MP2, dispersion-corrected semilocal density functional approximations (DFA), and the post-Kohn–Sham random phase approximation (RPA) for predicting binding energies of supramolecular complexes contained in the S66, L7, and S30L benchmarks. All binding energies are extrapolated to the basis set limit, corrected for basis set superposition errors, and compared to reference results of the domain-based local pair-natural orbital coupled-cluster (DLPNO-CCSD(T)) or better quality. Our results confirm that MP2 severely overestimates binding energies of large complexes, producing relative errors of over 100% for several benchmark compounds. RPA relative errors consistently range between 5-10%, significantly less than reported previously using smaller basis sets, whereas spin-scaled MP2 methods show limitations similar to MP2, albeit less pronounced, and empirically dispersion-corrected DFAs perform almost as well as RPA. Regression analysis reveals a systematic increase of relative MP2 binding energy errors with the system size at a rate of approximately 1‰ per valence electron, whereas the RPA and dispersion-corrected DFA relative errors are virtually independent of the system size. These observations are corroborated by a comparison of computed rotational constants of organic molecules to gas-phase spectroscopy data contained in the ROT34 benchmark. To analyze these results, an asymptotic adiabatic connection symmetry-adapted perturbation theory (AC-SAPT) is developed which uses monomers at full coupling whose ground-state density is constrained to the ground-state density of the complex. Using the fluctuation–dissipation theorem, we obtain a nonperturbative “screened second-order” expression for the dispersion energy in terms of monomer quantities which is exact for non-overlapping subsystems and free of induction terms; a first-order RPA-like approximation to the Hartree, exchange, and correlation kernel recovers the macroscopic Lifshitz limit. The AC-SAPT expansion of the interaction energy is obtained from Taylor expansion of the coupling strength integrand. Explicit expressions for the convergence radius of the AC-SAPT series are derived within RPA and MBPT and numerically evaluated. Whereas the AC-SAPT expansion is always convergent for nondegenerate monomers when RPA is used, it is found to spuriously diverge for second-order MBPT, except for the smallest and least polarizable monomers. The divergence of the AC-SAPT series within MBPT is numerically confirmed within RPA; prior numerical results on the convergence of the SAPT expansion for MBPT methods are revisited and support this conclusion once sufficiently high orders are included. The cause of the failure of MBPT methods for NIs of large systems is missing or incomplete “electrodynamic” screening of the Coulomb interaction due to induced particle–hole pairs between electrons in different monomers, leaving the effective interaction too strong for AC-SAPT to converge. Hence, MBPT cannot be considered reliable for quantitative predictions of NIs, even in moderately polarizable molecules with a few tens of atoms. The failure to accurately account for electrodynamic polarization makes MBPT qualitatively unsuitable for applications such as NIs of nanostructures, macromolecules, and soft materials; more robust non-perturbative approaches such as RPA or coupled cluster methods should be used instead whenever possible.<br>

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