Third-Order Optical Susceptibilities of Molecular and Polymeric Materials. Symmetry, Frequency, and Chromophore Structure Dependence as Probed by π-Electron Theory

1988 ◽  
Vol 134 ◽  
Author(s):  
D. Li ◽  
T. J. Marks ◽  
M. A. Ratner
Keyword(s):  
Perturbation Theory ◽  
Charge Transfer ◽  
Polymeric Materials ◽  
Molecular Structures ◽  
Conjugation Length ◽  
Third Order ◽  
Electron Theory ◽  
Electron Model ◽  
Structure Dependence ◽  
Model Hamiltonian

ABSTRACTThird-order optical susceptibilities (γijkl) can be efficiently analyzed for a variety of molecular structures employing perturbation theory and a PPP-SCF-SECI-DECI π-electron model Hamiltonian. The key, frequency tripling second hyperpolarizability γijkl(−3ω;ω,ω,ω) is calculated with full single and double CI. It is found that double excitations play a major role in third-order processes, and that γijkl, like the polarizability αij, is sensitive largely to the overall size (volume) of the π system, although charge transfer excitations may also contribute. The frequency dependence of v and correlations between γijkl and conjugation length are found for a series of trans polyenes.

Nonlinear Optical Materials Based on Benzobisthiazole. Electronic Structure/Molecular Architecture/Polarizability/Hyperpolarizability Relationships Derived from π-Electron Theory

1987 ◽  
Vol 109 ◽  
Author(s):  
Dequan Li ◽  
T. J. Marks ◽  
M. A. Ratner
Keyword(s):  
Charge Transfer ◽  
Optical Materials ◽  
Electron Cloud ◽  
Nonlinear Optical Materials ◽  
Molecular Architecture ◽  
Electron Theory ◽  
Electron Model ◽  
Molecular Dipole ◽  
Model Hamiltonian ◽  
Donor Acceptor

ABSTRACTFactors contributing to the polarizability (αij) and frequencydoubling hyperpolarizability (βijk) of 2-(p-dimethylaminophenyl)-6-(pnitrophenyl) benzo(l,2-d:4,5-d′ )blsthiazole (DNBT) are analyzed via perturbation theory and the PPP-SCF-MECI π-electron model Hamiltonian. While the observable part of β (βvec) is clearly identifiable with a small number of charge transfer excitations along the molecular dipole direction, a (and by inference, the second-order hyperpolarizability γ) is more closely related to the overall size (volume) of the π-electron cloud. As a consequence, βvec is far more sensitive to molecular distortions which affect donor-acceptor charge transfer interactions than is π. The more sensitive frequency dependence of βvec can be understood in terms of the three-photon character of this nonlinearity.

Addressing the Frenkel and charge transfer character of exciton states with a model Hamiltonian based on dimer calculations: Application to large aggregates of perylene bisimide

2021 ◽  
Vol 154 (12) ◽  
pp. 124101
Author(s):  
Sofia Canola ◽  
Giuseppe Bagnara ◽  
Yasi Dai ◽  
Gaetano Ricci ◽  
Alessandro Calzolari ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Perylene Bisimide ◽  
Model Hamiltonian

scholarly journals The axion-baryon coupling in SU(3) heavy baryon chiral perturbation theory

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Thomas Vonk ◽  
Feng-Kun Guo ◽  
Ulf-G. Meißner
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Heavy Baryon ◽  
Power Counting ◽  
Flavor Symmetry ◽  
Chiral Perturbation ◽  
Third Order ◽  
Stellar Objects ◽  
The Past ◽  
Dense Nuclear Matter

Abstract In the past, the axion-nucleon coupling has been calculated in the framework of SU(2) heavy baryon chiral perturbation theory up to third order in the chiral power counting. Here, we extend these earlier studies to the case of heavy baryon chiral perturbation theory with SU(3) flavor symmetry and derive the axion coupling to the full SU(3) baryon octet, showing that the axion also significantly couples to hyperons. As studies on dense nuclear matter suggest the possible existence of hyperons in stellar objects such as neutron stars, our results should have phenomenological implications related to the so-called axion window.

High efficient T-shape deep-red thermally activated delayed fluorescence emitter: substitution position effect

2021 ◽  
Author(s):  
Kai Zhang ◽  
Jianzhong Fan ◽  
Chuankui Wang ◽  
Lili Lin
Keyword(s):  
Charge Transfer ◽  
Position Effect ◽  
Luminescent Properties ◽  
Delayed Fluorescence ◽  
Molecular Structures ◽  
Transfer Property ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
High Efficient ◽  
The Relationship

Modulating the relationship between molecular structures and luminescent properties as well as the charge transfer property for deep-red thermally activated delayed fluorescence (TADF) emitters has always been a powerful challenge,...

Charge-transfer in Symmetry-Adapted Perturbation Theory

2009 ◽  
Vol 473 (1-3) ◽  
pp. 201-205 ◽  
Author(s):  
Anthony J. Stone ◽  
Alston J. Misquitta
Keyword(s):  
Perturbation Theory ◽  
Charge Transfer
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