Plane-wave calculations

Match the main features of the rocking curve first, using plane wave calculations and a single (sigma) polarisation. It shonld be possible to fit all the main peaks accnrately in spacing and approximately in intensity. Then begin refinement to match the intensities and widths. 

In the next two subsections, we describe collections of calculations that have been used to probe the physical accuracy of plane-wave DFT calculations. An important feature of plane-wave calculations is that they can be applied to bulk materials and other situations where the localized basis set approaches of molecular quantum chemistry are computationally impractical. To develop benchmarks for the performance of plane-wave methods for these properties, they must be compared with accurate experimental data. One of the reasons that benchmarking efforts for molecular quantum chemistry have been so successful is that very large collections of high-precision experimental data are available for small molecules. Data sets of similar size are not always available for the properties of interest in plane-wave DFT calculations, and this has limited the number of studies that have been performed with the aim of comparing predictions from plane-wave DFT with quantitative experimental information from a large number of materials. There are, of course, many hundreds of comparisons that have been made with individual experimental measurements. If you follow our advice and become familiar with the state-of-the-art literature in your particular area of interest, you will find examples of this kind. Below, we collect a number of examples where efforts have been made to compare the accuracy of plane-wave DFT calculations against systematic collections of experimental data. 

As an entrance point into the recent literature on using hybrid functionals within plane-wave calculations, read J. L. F. Da Silva, M. V. Ganduglia-Pirovano, J. Sauer, V. Bayer, and G. Kresse, Phys. Rev. B 75 (2007), 045121, and J. Paier,... 

The shape-consistent (or norm-conserving ) RECP approaches are most widely employed in calculations of heavy-atom molecules though ener-gy-adjusted/consistent pseudopotentials [58] by Stuttgart team are also actively used as well as the Huzinaga-type ab initio model potentials [66]. In plane wave calculations of many-atom systems and in molecular dynamics, the separable pseudopotentials [61, 62, 63] are more popular now because they provide linear scaling of computational effort with the basis set size in contrast to the radially-local RECPs. The nonrelativistic shape-consistent effective core potential was first proposed by Durand Barthelat [71] and then a modified scheme of the pseudoorbital construction was suggested by Christiansen et al. [72] and by Hamann et al. [73]. 

Calculated and experimental percent relaxations for various (0001) terminations of a-FejC. The DMol calculations were done according to the method outlined in [85]. LAPW refers to linear augmented plane wave calculations. 

Rynne et al. (1976) Mn, [Pg.57]

In more detail, our approach can be briefly summarized as follows gas-phase reactions, surface structures, and gas-surface reactions are treated at an ab initio level, using either cluster or periodic (plane-wave) calculations for surface structures, when appropriate. The results of these calculations are used to calculate reaction rate constants within the transition state (TS) or Rice-Ramsperger-Kassel-Marcus (RRKM) theory for bimolecular gas-phase reactions or unimolecular and surface reactions, respectively. The structure and energy characteristics of various surface groups can also be extracted from the results of ab initio calculations. Based on these results, a chemical mechanism can be constructed for both gas-phase reactions and surface growth. The film growth process is modeled within the kinetic Monte Carlo (KMC) approach, which provides an effective separation of fast and slow processes on an atomistic scale. The results of Monte Carlo (MC) simulations can be used in kinetic modeling based on formal chemical kinetics. 

The real space or extended basis description has the advantage of building upon accurate results from plane-wave calculations of the electronic structure [30]. Nevertheless, electronic structure calculations based on localized basis sets can become as accurate and predictive as plane-wave based results [31]. Plane-wave based calculations have the difficulty of how to transpose the calculated electronic structure into a form useful for transport calculations. Transport calculations are better suited for description in localized basis sets, hence transport based on ah initio localized basis codes are turning to be the best tool [32]. 

Full potential linearized-augmented-plane-wave calculations for 5d transition metals using the relativistic generalized gradient approximation... 

Trouiller N, Martins JL, Efficient pseudopotentials for plane-wave calculations, Phys Rev B, 43, 1993 (1991)... 

Troullier N, Martins JL (1991) Efficient Pseudopotentials for Plane-Wave Calculations, Phys Rev B 43 1993-2006... 

The overwhelming majority of the theoretical studies were performed on cluster models of the catalytic site, hi spite of the fact that the role of space confinement and the secondary interactions with the framework atoms is well-known, there are only a few electronic structure calculations on lattice models involving hydrocarbons, using either periodic DFT calculations, or embedding methods. In this brief account of the subject we attempt to overview some of the recent computational results of the literature and present some new data obtained from ab initio DFT pseudopotential plane wave calculations on Cl - C4 alkanes in the chabazite framework. 

Ab initio DFT pseudopotential plane wave calculations were performed to study the transition structures and the corresponding activation energies for... 

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