79 research outputs found

    The nature of three-body interactions in DFT: exchange and polarization effects

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    We propose a physically motivated decomposition of DFT 3-body nonadditive interaction energies into the exchange and density-deformation (polarization) components. The exchange component represents the effect of the Pauli exclusion in the wave function of the trimer and is found to be challenging for density functional approximations (DFAs). The remaining density-deformation nonadditivity is less dependent upon the DFAs. Numerical demonstration is carried out for rare gas atom trimers, Ar2_2-HX (X = F, Cl) complexes, and small hydrogen-bonded and van der Waals molecular systems. None of the tested semilocal, hybrid, and range-separated DFAs properly accounts for the nonadditive exchange in dispersion-bonded trimers. By contrast, for hydrogen-bonded systems range-separated hybrids achieve a qualitative agreement to within 20% of the reference exchange energy. A reliable performance for all systems is obtained only when the monomers interact through the Hartree-Fock potential in the dispersion-free Pauli Blockade scheme. Additionally, we identify the nonadditive second-order exchange-dispersion energy as an important but overlooked contribution in force-field-like dispersion corrections. Our results suggest that range-separated functionals do not include this component although semilocal and global hybrid DFAs appear to imitate it in the short range

    Density Functional Theory Approach to Noncovalent Interactions via Interacting Monomer Densities

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    A recently proposed "DFT+dispersion" treatment (Rajchel et al., Phys. Rev. Lett., 2010, 104, 163001) is described in detail and illustrated by more examples. The formalism derives the dispersion-free density functional theory (DFT) interaction energy and combines it with the dispersion energy from separate DFT calculations. It consists in the self-consistent polarization of DFT monomers restrained by the exclusion principle via the Pauli blockade technique. Within the monomers a complete exchange-correlation potential should be used, but between them only the exact exchange operates. The applications to wide range of molecular complexes from rare-gas dimers to H-bonds to pi-electron interactions show good agreement with benchmark values.Comment: 9 pages, 5 figures, 2 tables, REVTeX

    Dispersion-free component of non-covalent interaction via mutual polarization of fragment densities

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    Comprehensive tests within a diverse set of noncovalently bonded systems are carried out to assess the performance of the recently-developed dispersion-free approach in the framework of density functional theory [Ł. Rajchel, P. Żuchowski, M. Szczęśniak, and G. Chałasiński, Phys. Rev. Lett. 104, 163001 (2010)]10.1103/PhysRevLett.104.163001. A numerical algorithm which cures the convergence problems of the previous implementation is presented.Łukasz Rajche

    An Assortment of Evolutionary Computation Techniques (AECT) in gaming

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    © 2020, Springer-Verlag London Ltd., part of Springer Nature. Real-time strategy (RTS) games differ as they persist in varying scenarios and states. These games enable an integrated correspondence of non-player characters (NPCs) to appear as an autodidact in a dynamic environment, thereby resulting in a combined attack of NPCs on human-controlled character (HCC) with maximal damage. This research aims to empower NPCs with intelligent traits. Therefore, we instigate an assortment of ant colony optimization (ACO) with genetic algorithm (GA)-based approach to first-person shooter (FPS) game, i.e., Zombies Redemption (ZR). Eminent NPCs with best-fit genes are elected to spawn NPCs over generations and game levels as yielded by GA. Moreover, NPCs empower ACO to elect an optimal path with diverse incentives and less likelihood of getting shot. The proposed technique ZR is novel as it integrates ACO and GA in FPS games where NPC will use ACO to exploit and optimize its current strategy. GA will be used to share and explore strategy among NPCs. Moreover, it involves an elaboration of the mechanism of evolution through parameter utilization and updation over the generations. ZR is played by 450 players with varying levels having the evolving traits of NPCs and environmental constraints in order to accumulate experimental results. Results revealed improvement in NPCs performance as the game proceeds

    Protection block separateness of deposits by laser scanning

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    W artykule przedstawiono metodę identyfikacji bloczności złoża, pozwalającą na racjonalne wykorzystanie zasobów. W celu wyodrębnienia partii blocznych poszczególnych rejonów złoża oraz dostosowania techniki urabiania, oprócz tradycyjnych badań podzielności ciosowej, wykorzystano także pomiary skaningowe. Przedstawiony sposób ochrony partii blocznych zastosowaniem nowoczesnych narzędzi w postaci skanera laserowego, stwarza nowe możliwości optymalizacji efektywności eksploatacji i poprawy bezpieczeństwa wydobycia. Przedstawiono procedurę aplikacyjną techniki strzelniczej, do wspomagania eksploatacji złóż blocznych.In the article were presented results of the conducted identification of block separateness deposits. It shows that the laser scanning could be good alternative to determinaterock's block separateness. Results of the research allow to improve the rational use of resources. It also presents that obtaining of block elements is possible
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