VASP Vienna Ab Initio Simulation

The experiments at the Pohang Accelerator Laboratory were supported in part by MOST and Pohang Iron and Steel (POSCO). Special thank to Isao Tanaka for supporting the ab initio total-energy and molecular dynamics program VASP (Vienna ab initio simulation package). 

Initial optimization studies were performed with VASP (Vienna Ab Initio Simulation Protocol). Later on, optimization studies were repeated with Car-Parrinello MD (CPMD). With CPMD, the transition from upright to tilted shifts to a slightly larger value, dec 6.7 A. 

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. 

The density functional calculations were performed using the Vienna Ab Initio Simulation Package (VASP). ° The spin-polarized generalized gradient approximation, Perdue—Wang exchange correlation function, and ultrasoft pseudopotentials were used. ... 

The Vienna Ab Initio Simulation Package (VASP) program33,34 was developed to carry out calculations to obtain the fluctuation trajectory of the selected models. The VASP program uses a rather traditional self-consistency scheme to evaluate the instantaneous electronic ground-state at each molecular dynamics (MD) step so that the wavefunction can be converged to the Born-Oppenheimer surface at each time-step. 

The Vienna Ab Initio Simulation Package (VASP) has been used to perform the periodic structure calculationsAll atoms have been allowed to relax completely within the periodic unit cell. The large 12-membered ring Mordenite has been used for this study as this zeolite has a relatively small unit cell (i.e. 146 atoms). It has previously been studied by Demuth et al. . For our zeolite model, the Si/Al ratio is 23, and the geometry of the unit cell is described by a = 13.648 k, b = 13.672 A, c = 15.105 A, a = 96.792 >5 =... 

At present three different codes are widely used for calculations of the structural and spectroscopic properties of H-bonded crystals, for example see Refs. [82-85]. The Car-Parrinello molecular dynamics (CPMD) program [86] and the Vienna ab initio simulation program (VASP) [87, 88] use a plane wave basis set, while an atom centered set is used with periodic boundary conditions in the CRYSTAL... 

The Vienna Ab-Initio Simulation Program VASP An Efficient and Versatile Tool for Studying the Structural, Dynamic, and... 

The main codes for periodic DFT calculations differ by the choice of basis sets. There are three possibilities atomic orbitals (CRYSTAL, SIESTA, GAUSSIAN codes), plane waves (Vienna ab initio simulation package (VASP), CASTEP, DACAPO, CPMD, Quantum-ESPRESSO codes), or both with a partition of the space between atomic spheres and intermediate regions (APW, LMTO, KKR, WIEN2K codes). We will shortly describe the advantage and disadvantage of the two extreme choices taking CRYSTAL and VASP as representative codes. 

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