Electronic structure of poly(pyrrole–thiophene) copolymers: Design of polymeric quasi‐one‐dimensional superlattices

Bakhshi, A.K.; Ladik, J.

doi:10.1002/qua.560420433

Cited by 11 publications

(4 citation statements)

References 40 publications

(17 reference statements)

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“…In this way it should be possible to reach theoretical predictions about useful candidates for synthetic metals. Important ab initio investigations on the search for low-gap polymers (in different directions regarding the chemical structure) were reported by Bakshi et al [46][47][48][49][50][51]. For a comprehensive review of the large amount of work performed by the group of Ladik on this topic see [52].…”

Section: Introductionmentioning

confidence: 99%

Multiquantum states derived from Davydov'sansatz: II. An exact special case solution for the Su-Schrieffer-Heeger Hamiltonian and its relation to the state

Förner¹

1998

J. Phys.: Condens. Matter

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We present the derivation of an exact special case solution (for a classical lattice) for the Su-Schrieffer-Heeger model for the calculation of soliton dynamics in trans-polyacetylene. Our solution is exact, in the sense that the ansatz state yields an exact solution provided that the equations of motion for its parameters are obeyed. However, these equations can be solved only numerically (in principle to any desired accuracy), not analytically. The model is applied to time simulations of neutral solitons as a function of temperature. We find agreement of the results of our time simulations with experimental data on the mobility of neutral solitons in the system. Comparative calculations using the completely adiabatic model indicate that the results of this model are at variance both with experiment and with those of our model. A simple consideration of the potential barriers for soliton displacement leads to an overestimation of the soliton mobility for low temperatures and an underestimation for higher ones. In an appendix we discuss in some detail the relationship of this exact solution with the | 2 state ansatz as presented in our previous paper. We find that the ansatz state and the exact solution yield identical results for lattice momenta, displacements and site occupancies, but differ in a time dependent phase factor. Thus spectra computed with the dynamics resulting from the exact solution for the classical lattice on one hand and from the ansatz state on the other would differ from each other.

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Section: Introductionmentioning

confidence: 99%

Multiquantum states derived from Davydov'sansatz: II. An exact special case solution for the Su-Schrieffer-Heeger Hamiltonian and its relation to the state

Förner¹

1998

J. Phys.: Condens. Matter

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Section: Model Heterostructuresmentioning

confidence: 99%

“…Studies of the electronic states of heterostructures similar to these have been reported by other authors, employing conventional quantum-chemical or solid-state methods. [39][40][41][42][43][44] IV. COMPUTATIONAL IMPLEMENTATION A practical implementation of the EMO theory requires four input parameters for each parent polymer: the HOCO and LUCO energies and the hole and electron effective masses.…”

Section: Model Heterostructuresmentioning

confidence: 99%

Envelope molecular-orbital theory of extended systems. I. Electronic states of organic quasilinear nanoheterostructures

Arce

Perdomo-Ortiz

Zambrano

et al. 2011

The Journal of Chemical Physics

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A conceptually appealing and computationally economical course-grained molecular-orbital (MO) theory for extended quasi-linear molecular heterostructures is presented. The formalism, which is based on a straightforward adaptation, by including explicitly the vacuum, of the envelope-function approximation widely employed in solid-state physics, leads to a mapping of the three-dimensional single-particle eigenvalue equations into simple one-dimensional hole and electron Schrödinger-like equations with piecewise-constant effective potentials and masses. The eigenfunctions of these equations are envelope MO's in which the short-wavelength oscillations present in the full MO's, associated with the atomistic details of the molecular potential, are smoothed out automatically. The approach is illustrated by calculating the envelope MO's of high-lying occupied and low-lying virtual π states in prototypical nanometric heterostructures constituted by oligomers of polyacetylene and polydiacetylene. Comparison with atomistic electronic-structure calculations reveals that the envelope-MO energies agree very well with the energies of the π MO's and that the envelope MO's describe precisely the long-wavelength variations of the π MO's. This envelope MO theory, which is generalizable to extended systems of any dimensionality, is seen to provide a useful tool for the qualitative interpretation and quantitative prediction of the single-particle quantum states in mesoscopic molecular structures and the design of nanometric molecular devices with tailored energy levels and wavefunctions.PACS numbers: 36.20.Kd, 71.20.Rv,

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“…Quantum-chemical calculations have been carried out for oligothiophenes 13,14 and for copolymers based on pyrrole and thiophene units 15 in order to understand the properties of the respective polymers in neutral and doped states. It is worth mentioning that only oligomers with anti chains ͓Fig.…”

Section: Introductionmentioning

confidence: 99%

Electronic structure of poly(tri-heterocycle) based on furan and thiophene: The role of the syn links

Doretto

Laks

2002

The Journal of Chemical Physics

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The electronic structures of poly(OSO) oligomers were theoretically analyzed. Models based on neutral and charged oligomers whose all rings (3<n<15) are linked to have syn or anti chains were considered. Geometrical optimizations were carried out at the semiempirical level using the parametric method 3 (PM3). The results indicated that the chain of the syn oligomer have a small curvature. For singly oxidized oligomers, the positive charge is concentrated around furan rings with a quinoid bond alternation pattern that extends at most six rings. For doubly oxidized oligomers, we also found a quinoid structure which extends up to eight rings. The energy of the electronic transitions and their associated oscillator strength values were also calculated for neutral and charged oligomers, so the UV–vis absorption spectra is presented. The calculations were done using the intermediate neglect of differential overlap Hamiltonian in combination with the single configuration–interaction technique in order to include correlations effects. The results indicated that the difference between the lowest unoccupied molecular orbital and highest occupied molecular orbital energies of the neutral oligomers are weakly correlated to the kind of their chains, although the different intensities of the lowest energy absorption peaks can be related to rings linked at the syn form.

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Electronic structure of poly(pyrrole–thiophene) copolymers: Design of polymeric quasi‐one‐dimensional superlattices

Cited by 11 publications

References 40 publications

Multiquantum states derived from Davydov'sansatz: II. An exact special case solution for the Su-Schrieffer-Heeger Hamiltonian and its relation to the state

Multiquantum states derived from Davydov'sansatz: II. An exact special case solution for the Su-Schrieffer-Heeger Hamiltonian and its relation to the state

Envelope molecular-orbital theory of extended systems. I. Electronic states of organic quasilinear nanoheterostructures

Electronic structure of poly(tri-heterocycle) based on furan and thiophene: The role of the syn links

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