VASP software

Figure 3.6 shows a possible 3D molecular arrangement of a Zn " cation surrounded by six H2O molecules. The structure was optimized by performing first-principles periodic density functional calculations using projector-augmented wave (PAW) potentials [23, 24] for describing electron-ion interactions, within the Vienna Ab initio Simulation Package (VASP) software [25]. 

Moreover, P4VASP software is mainly employed to deal with the VASP-calculation results to obtain the visualization data. Visualization for... 

Based on the same underlying principles as the molecular-based quantum methods, solid state quantum mechanics represents bulk material using periodic boundary conditions. The imposition of these boundary conditions means that it becomes possible to expand the electron density in periodic functions such as plane waves, as an alternative to the atom-based functions used in the molecular case. The efficiency of the calculations is enhanced by the use of pseudo-potentials to represent the core electrons and to make the electron density as smooth as possible near the nucleus, hence reducing the complexity of the plane wave expansion of the electron density. Because of the number of choices available for pseudo potentials, basis sets and whether calculations are done in real or reciprocal space, there are many choices of software for performing solid state quantum mechanical calculations. A few examples which have been used in crystal structure prediction include the Vienna ab initio Simulation Package (VASP), CASTEP and CRYSTAL. " A wider ranging introduction to the area can be found in the references. ... 

At the CLs of PEMFCs, the atomistic scale models are needed to describe the interactions between the atoms and then to predict the lattice structures and chemical reactions due to charge transfer. There are many well-known software packages used in materials science and quantum chemistry, suchasADF, AMPAC, ASE, CASTEP, HyperChem, SIESTA, GAUSSIAN, VASP, etc. Practically all of these codes are based on Density Functional Theory (DFT) and some are employed to analyze the TPB region in the CLs of PEMFC. 

The properties of these systems are obtained from published experimental data and/or the electronic structure calculations. For crystalline structures, the electronic structure calculations are performed with plane-wave DFT calculations using the software VASP (Vienna Ab initio Simulation Package) with appropriate pseudopotential and exchange-correlation functionals (US-LLDA or PAW-PBE). For molecular systems, the electronic structure calculations are performed using the Gaussian09 computational chemistry software package. Table 7.1 shows the fitting database and predicted values from the COMB potential for Cu. 

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