Journal ArticleDOI
A density-matrix-based simulated annealing (sa) technique for locating minimum energy structures on the neutral polythiophene potential energy surface
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In this paper, a modified version of the Su-Schrieffer-Heeger Hamiltonian is used to generate the PES and the unitary transformation of the density variables as the bond lengths change during random reconfiguring moves.Abstract:
We use the elements of the single particle density matrix in the atomic orbital basis as the basic variables and the simulated annealing method as the optimization tool to locate the global minima on the potential surfaces of polythiophene and polyselenophene oligomers (PT)n, (PS)n with n up to 100. A modified version of the Su–Schrieffer–Heeger Hamiltonian is used to generate the PES and the unitary transformation of the density variables as the bond lengths change during random reconfiguring moves. The cost effectiveness of the method is analyzed.read more
Citations
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Determining the DNA stability parameters for the breathing dynamics of heterogeneous DNA by stochastic optimization.
TL;DR: In this article, the thermodynamic stability parameters (nearest neighbor stacking and hydrogen bonding free energies) of double-stranded DNA molecules can be inferred reliably from time series of the size fluctuations (breathing) of local denaturation zones (bubbles).
Journal ArticleDOI
Determining the DNA stability parameters for the breathing dynamics of heterogeneous DNA by stochastic optimization
TL;DR: It is shown that even noisy time series allow the identification of the stability parameters at remarkable accuracy, and this method will be useful to obtain the DNA stacking and hydrogen bonding free energies from single bubble breathing assays rather than equilibrium data.
Journal ArticleDOI
Study of structure and spectroscopy of water–hydroxide ion clusters: A combined simulated annealing and DFT-based approach
TL;DR: In this article, the authors explored the use of stochastic optimizer, namely simulated annealing (SA) followed by density function theory (DFT)-based strategy for evaluating the structure and infrared spectroscopy of (H2O) clusters where n = 1 − 6.
Journal ArticleDOI
Finding the optimum activation energy in DNA breathing dynamics: a simulated annealing approach
TL;DR: In this article, the authors demonstrate how the stochastic global optimization scheme of simulated annealing can be used to evaluate optimum parameters in the problem of DNA breathing dynamics and demonstrate that the method overcomes even large noise in the input surrogate data.
Journal ArticleDOI
Blending Determinism with Evolutionary Computing: Applications to the Calculation of the Molecular Electronic Structure of Polythiophene.
TL;DR: The method is further tested successfully with optimization of the geometry of bipolaron-doped long PT chains and the robustness and the performance levels of variants of the algorithm are analyzed and compared with those of other derivative free methods.
References
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Journal ArticleDOI
Evidence of intrinsic extended pi -bonding band and metalliclike behavior in undoped and doped electropolymerized poly(3-methylthiophene) films.
TL;DR: Spectroscopie de photoemission UV et RX de la structure electronique de ce polymere electropolymerise et dope par ClO 4 −
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The instability of a bipolaron versus two polarons: charge localization in cyclo-dodecathiophene
TL;DR: In this paper, the electronic structure and geometry of polythiophene, using cyclo-dodecathiophene as a model compound, are calculated and their stability is investigated.
Journal ArticleDOI
Polarons in semiconducting polymers: Study within an extended Holstein model
TL;DR: In this paper, a study of electron-hole phonon interaction and polaron formation in semiconducting polymers within an extended Holstein model is presented, where a minimization of the lowest electronic state of this Hamiltonian with respect to lattice degrees of freedom yields the polaronic ground state.
Journal ArticleDOI
Quantum chemical studies on polythiophenes containing heterocyclic substituents: Effect of structure on the band gap
TL;DR: This study illustrates the usefulness of quantum-mechanical calculations in understanding the effects of various structural parameters on optical band gap by comparing predicted band-gap values with experimental band gaps obtained from optical-absorption edge.
Journal ArticleDOI
Insulator-to-metal transition in polythiophene.
TL;DR: The results are consistent with the following: the bipolaron lattice does not present a finite density of states at the Fermi energy at any doping level; and bipolaron clusters show an insulator-to-metal transition at 8 mol % doping level.
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