Vienna ab initio simulations

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 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). 

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. 

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]. 

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