Browsing by Author "Mazur, Grzegorz"

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Automatized Parameterization of DFTB Using Particle Swarm Optimization
(2016-01)
Chou, Chien-Pin
;
Nishimura, Yoshifumi
;
Fan, Chin-Chai
;
Mazur, Grzegorz
;
Irle, Stephan
We present a novel density-functional tight-binding (DFTB) parametrization toolkit developed to optimize the parameters of various DFTB models in a fully automatized fashion. The main features of the algorithm, based on the particle swarm optimization technique, are discussed, and a number of initial pilot applications of the developed methodology to molecular and solid systems are presented.
Automatized Parameterization of DFTB Using Particle Swarm Optimization
(2016-01-01)
Chou, Chien-Pin
;
Nishimura, Yoshifumi
;
Fan, Chin-Chai
;
Mazur, Grzegorz
;
Irle, Stephan
We present a novel density-functional tight-binding (DFTB) parametrization toolkit developed to optimize the parameters of various DFTB models in a fully automatized fashion. The main features of the algorithm, based on the particle swarm optimization technique, are discussed, and a number of initial pilot applications of the developed methodology to molecular and solid systems are presented.
Automatized Parameterization of the Density-functional Tight-binding Method. II. Two-center Integrals
(2016-01-01)
Witek, Henryk A.
;
Chou, Chien-Pin
;
Mazur, Grzegorz
;
Nishimura, Yoshifumi
;
Irle, Stephan
We present an efficient numerical integration scheme (TWOCENT) to be used in the context of automatized parameterization of the density-functional tight-binding (DFTB) method. The accuracy of the integration process is assessed and its range of applicability is discussed. The functionality of the developed code is tested by reproducing the electronic portion of the existing mio parameter sets and by reproducing a series of reference DFT band structures of elemental solids.
Automatized Parameterization of the Density-functional Tight-binding Method. II. Two-center Integrals
(2016-01)
Witek, Henryk A.
;
Chou, Chien-Pin
;
Mazur, Grzegorz
;
Nishimura, Yoshifumi
;
Irle, Stephan
We present an efficient numerical integration scheme (TWOCENT) to be used in the context of automatized parameterization of the density-functional tight-binding (DFTB) method. The accuracy of the integration process is assessed and its range of applicability is discussed. The functionality of the developed code is tested by reproducing the electronic portion of the existing mio parameter sets and by reproducing a series of reference DFT band structures of elemental solids.
Transition dipole moments of charge transfer excitations in one-component molecular crystals
(2012-03-13)
Mazur, Grzegorz
;
Petelenz, Piotr
;
Slawik, Michal
;
應用化學系
;
Department of Applied Chemistry
Owing to the peculiar structure of oligothiophene crystals, their low-energy b-polarized spectra are dominated by the contributions from charge transfer states almost free from Frenkel state admixtures, offering a unique opportunity for in-depth studies of the former. Here, a simple model, rooted in the Mulliken theory of charge transfer transitions, is proposed to estimate the relevant transition dipole moments. For sexithiophene, the resultant estimate agrees with the value used in the recent detailed theoretical reproduction of the absorption and electroabsorption spectra, and is found to be consistent with other input parameters. The approach presented here is readily applicable for other one-component molecular crystals, providing a simple method to estimate the intrinsic transition dipoles of charge transfer configurations. (C) 2012 Elsevier B.V. All rights reserved.