Automatic generation of matrix element derivatives for tight binding models

Elena, Alin M.; Meister, Matthias

doi:10.1103/physrevb.72.165107

Cited by 8 publications

(8 citation statements)

References 9 publications

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“…With the increasing number of basis functions there is of course an increased computational cost associated with the calculations. In order to accommodate the use of f orbital functions within PLATO, we have implemented the generic Slater-Koster routines detailed in [24,25]. This recursive approach allows us to employ basis sets containing basis functions with any angular component.…”

Section: Methodsmentioning

confidence: 99%

Adsorption of N@C60 on Si(100)

2009

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The interactions between C 60 molecules and the Si(100) surface, as well as the interactions between the endohedrally doped N@C 60 molecules and the Si(100) surface have been explored via ab initio total energy calculations. Configurations which have the cage located upon the dimer row bonded to two dimers (r2) and within the dimer trench bonded to four dimers (t4) have been investigated, as these have previously been found to be the most stable for the C 60 molecule. We show that our results for the adsorption of the C 60 molecule upon the Si(100) surface are comparable with previous studies. We have investigated the differences between the adsorption of the C 60 and N@C 60 molecules upon the Si(100) surface and found that there are only minimal differences. Two interesting cases are the r2g and t4d configurations, as they both exhibit differences that are not present in the other configurations. These subtle differences have been explored in-depth. It is shown that the effects on the endohedral nitrogen atom, due to its placement within the fullerene cage, are small. Bader analysis has been used to explore differences between the C 60 and N@C 60 molecules.

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Section: Methodsmentioning

confidence: 99%

Adsorption of N@C60 on Si(100)

2009

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“…The angular dependences of the hopping integrals can be represented analytically 35 or may be computed on-the-fly. 39 We represent the radial dependence of the bond integrals by a product of exponentials, that is, where R 0 is an equilibrium or reference bond length, h ll ′ τ (R 0 ) is the value of the bond integral at R = R 0 , and { A m } are adjustable parameters. This form for the bond integrals is motivated physically by the radial dependence of Slater-type orbitals, leads to a fast decay with increasing R, and is computationally convenient.…”

Section: A Self-consistent Tight Binding Model For Hydrocarbonsmentioning

confidence: 99%

Extended Lagrangian Born-Oppenheimer molecular dynamics simulations of the shock-induced chemistry of phenylacetylene

Cawkwell

Niklasson

Dattelbaum

2015

The Journal of Chemical Physics

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The initial chemical events that occur during the shock compression of liquid phenylacetylene have been investigated using self-consistent tight binding molecular dynamics simulations. The extended Lagrangian Born-Oppenheimer molecular dynamics formalism enabled us to compute microcanonical trajectories with precise conservation of the total energy. Our simulations revealed that the first density-increasing step under shock compression arises from the polymerization of phenylacetylene molecules at the acetylene moiety. The application of electronic structure-based molecular dynamics with long-term conservation of the total energy enabled us to identify electronic signatures of reactivity via monitoring changes in the HOMO-LUMO gap, and to capture directly adiabatic shock heating, transient non-equilibrium states, and changes in temperature arising from exothermic chemistry in classical molecular dynamics trajectories.

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“…The direct implementation of such tables and particularly the derivatives, which are required for the evaluation of the forces, become incredibly difficult to implement. Recently work has been performed on formalisms for the automatic generation of Slater-Koster tables [10,11]. We have implemented these approaches in Plato and can use them to apply the Slater-Koster rules to arbitrary angular momenta.…”

Section: Integral Tablesmentioning

confidence: 99%

“…The use of integral tables adds complexity to Plato and requires the generation of the tables but means that these integrals can be performed very accurately relatively cheaply. Until recently it was very difficult to deal with f-orbitals and beyond using an integral table approach but this has been addressed by the emergence of recursive techniques for calculating Slater-Koster contributions [10,11].…”

Section: Overview Of Platomentioning

confidence: 99%

Plato: A localised orbital based density functional theory code

Kenny¹,

Horsfield²

2009

Computer Physics Communications

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The Plato package allows both orthogonal and non-orthogonal tight-binding as well as density functional theory (DFT) calculations to be performed within a single framework. The package also provides extensive tools for analysing the results of simulations as well as a number of tools for creating input files. The code is based upon the ideas first discussed in [1] with extensions to allow highquality DFT calculations to be performed. DFT calculations can utilise either the local density approximation or the generalised gradient approximation. Basis sets from minimal basis through to ones containing multiple radial functions per angular momenta and polarisation functions can be used. Illustrations of how the package has been employed are given along with instructions for its utilisation. Nature of problem: Density functional theory study of electronic structure and total energies of molecules, crystals and surfaces. PACSSolution method: Localised orbital based density functional theory.Restrictions: Tight-binding and density functional theory only, no exact exchange.Unusual features: Both atom centred and uniform meshes available. Can deal with arbitrary angular momenta for orbitals, whilst still retaining Slater-Koster tables for accuracy. Additional comments:Running time: Test cases will run in a few minutes, large calculations may run for several days.

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Automatic generation of matrix element derivatives for tight binding models

Cited by 8 publications

References 9 publications

Adsorption of N@C60 on Si(100)

Adsorption of N@C60 on Si(100)

Extended Lagrangian Born-Oppenheimer molecular dynamics simulations of the shock-induced chemistry of phenylacetylene

Plato: A localised orbital based density functional theory code

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