Auxiliary basis sets to approximate Coulomb potentials (Chem. Phys. Letters 240 (1995) 283-290)

Eichkorn, Karin; Treutler, Oliver; Öhm, Holger; Häser, Marco; Ahlrichs, Reinhart

doi:10.1016/0009-2614(95)00838-u

Cited by 2,076 publications

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“…All optimized structures and energies (including those of the transition states) were calculated using the generalized gradient approximation Becke-Perdew density functional BP86 6,7 with the resolution of identity (RI) approximation [8][9][10] . Atom-centered basis sets were used for all atoms in this work: the large def2-TZVPP basis set for amination/hydrolysis thermodynamic calculations and the smaller def-SV(P) basis set for both cluster models 11,12 .…”

Section: Methodsmentioning

confidence: 99%

Effect of Reaction Mechanism on Precursor Exposure Time in Atomic Layer Deposition of Silicon Oxide and Silicon Nitride

Murray

Elliott

Hausmann

et al. 2014

ACS Appl. Mater. Interfaces

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Access to the full text of the published version may require a subscription. ABSTRACT: Atomic layer deposition (ALD) of highly conformal, silicon-based dielectric thin films has become necessary due the continuing decrease of feature size in microelectronic devices. The ALD of oxides and nitrides is usually thought to be mechanistically similar, but plasma-enhanced ALD of silicon nitride is found to be problematic, while that of silicon oxide is straightforward. To find why, the ALD of silicon nitride and silicon oxide dielectric films was studied by applying ab initio methods to theoretical models for proposed surface reaction mechanisms. The thermodynamic energies for the elimination of functional groups from different silicon precursors reacting with simple model molecules were calculated using density functional theory (DFT), explaining the lower reactivity of precursors towards the deposition of silicon nitride relative to silicon oxide seen in experiments, but not explaining the trends between precursors. Using more realistic cluster models of amine and hydroxyl covered surfaces, the structures and energies were calculated of reaction pathways for chemisorption of different silicon precursors via functional group elimination, with more success. DFT calculations identified the initial physisorption step as crucial towards deposition and this step was thus used to predict the ALD reactivity of a range of amino-silane precursors, yielding good agreement with experiment. The retention of hydrogen within silicon nitride films but not in silicon oxide observed in FTIR spectra was accounted for by the theoretical calculations and helped verify the application of the model. Rights

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Section: Methodsmentioning

confidence: 99%

Effect of Reaction Mechanism on Precursor Exposure Time in Atomic Layer Deposition of Silicon Oxide and Silicon Nitride

Murray

Elliott

Hausmann

et al. 2014

ACS Appl. Mater. Interfaces

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“…[39][40][41] The calculations employ the BP86 parametrization of the exchange correlation functional and a triple-valence plus polarization (TZVP) basis set for all atoms. 42 It has been shown that this approach gives good agreement with experimental data.…”

Section: Methodsmentioning

confidence: 99%

H₂ Adsorption on 3d Transition Metal Clusters: A Combined Infrared Spectroscopy and Density Functional Study

et al. 2008

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The adsorption of H 2 on a series of gas-phase transition metal (scandium, vanadium, iron, cobalt, and nickel) clusters containing up to 20 metal atoms is studied using IR-multiple photon dissociation spectroscopy complemented with density functional theory based calculations. Comparison of the experimental and calculated spectra gives information on hydrogen-bonding geometries. The adsorption of H 2 is found to be exclusively dissociative on Sc n O + , V n + , Fe n + , and Co n + , and both atomic and molecularly chemisorbed hydrogen is present in Ni n H m + complexes. It is shown that hydrogen adsorption geometries depend on the elemental composition as well as on the cluster size and that the adsorption sites are different for clusters and extended surfaces. In contrast to what is observed for extended metal surfaces, where hydrogen has a preference for high coordination sites, hydrogen can be both 2-or 3-fold coordinated to cationic metal clusters.

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“…the def2-QZVP basis set with discarded f and g-type functions on hydrogen and other atoms, respectively) [49,50,51]. All DFT calculations were sped up by expanding the Coulomb interactions in auxiliary basis sets, the resolution-of-identity approximation, using the corresponding auxiliary basis sets [52,53]. The calculations also used the multipole-accelerated resolution-of-identity J approach (MARIJ) [54].…”

Section: Dft-d Calculationsmentioning

confidence: 99%

Free-energy perturbation and quantum mechanical study of SAMPL4 octa-acid host–guest binding energies

Mikulskis

Cioloboc

Andrejić

et al. 2014

J Comput Aided Mol Des

220

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Free-energy perturbation and quantum mechanical study of SAMPL4 octa-acid hostguest binding energies. Link to publication Citation for published version (APA): Mikulskis, P., Cioloboc, D., Andrejić, M., Khare, S., Brorsson, J., Genheden, S., ... Ryde, U. (2014). Free-energy perturbation and quantum mechanical study of SAMPL4 octa-acid host-guest binding energies. Journal of Computer-Aided Molecular Design, 28(4), 375-400. DOI: 10.1007/s10822-014-9739-x General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal AbstractWe have estimated free energies for the binding of nine cyclic carboxylate guest molecules to the octa-acid host in the SAMPL4 blind-test challenge with four different approaches. First, we used standard free-energy perturbation calculations of relative binding affinities, performed at the molecular-mechanics (MM) level with TIP3P waters, the GAFF force field, and two different sets of charges for the host and the guest, obtained either with the restrained electrostatic potential or AM1-BCC methods. Both charge sets give good and nearly identical results, with a mean absolute deviation (MAD) of 4 kJ/mol and a correlation coefficient (R 2 ) of 0.8 compared to experimental results. Second, we tried to improve these predictions with 28 800 density-functional theory (DFT) calculations for selected snapshots and the non-Boltzmann Bennett acceptance-ratio method, but this led to much worse results, probably because of a too large difference between the MM and DFT potential-energy functions. Third, we tried to calculate absolute affinities using minimised DFT structures. This gave intermediate-quality results with MADs of 5-9 kJ/mol and R 2 = 0.6-0.8, depending on how the structures were obtained. Finally, we tried to improve these results using local coupled-cluster calculations with single and double excitations, and non-iterative perturbative treatment of triple excitations (LCCSD(T0)), employing the polarisable multipole interactions with supermolecular pairs approach. Unfortunately, this only degraded the predictions, probably because a mismatch between the solvation energies obtained at the DFT and LCCSD(T0) levels.Key Words: binding affinities, host-guest, free-energies perturbation, density-functional calculations, CCSD(T), polarisable multipole interactions. 2 IntroductionOne of the largest challenges of computational chemistry is to predict the binding affinity of a small ligand to a larger receptor molecule, e.g. a drug candidate to its receptor prot...

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Auxiliary basis sets to approximate Coulomb potentials (Chem. Phys. Letters 240 (1995) 283-290)

Cited by 2,076 publications

References 0 publications

Effect of Reaction Mechanism on Precursor Exposure Time in Atomic Layer Deposition of Silicon Oxide and Silicon Nitride

Effect of Reaction Mechanism on Precursor Exposure Time in Atomic Layer Deposition of Silicon Oxide and Silicon Nitride

H₂ Adsorption on 3d Transition Metal Clusters: A Combined Infrared Spectroscopy and Density Functional Study

Free-energy perturbation and quantum mechanical study of SAMPL4 octa-acid host–guest binding energies

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Auxiliary basis sets to approximate Coulomb potentials (Chem. Phys. Letters 240 (1995) 283-290)

Cited by 2,076 publications

References 0 publications

Effect of Reaction Mechanism on Precursor Exposure Time in Atomic Layer Deposition of Silicon Oxide and Silicon Nitride

Effect of Reaction Mechanism on Precursor Exposure Time in Atomic Layer Deposition of Silicon Oxide and Silicon Nitride

H2 Adsorption on 3d Transition Metal Clusters: A Combined Infrared Spectroscopy and Density Functional Study

Free-energy perturbation and quantum mechanical study of SAMPL4 octa-acid host–guest binding energies

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H₂ Adsorption on 3d Transition Metal Clusters: A Combined Infrared Spectroscopy and Density Functional Study