Vanderbilt ultrasoft pseudopotential

Density functional theory calculations are carried out using the CPMD code, which allows to simulate systems with periodic boundary conditions [31]. The BP exchange correlation functional [32] is used with ultrasoft Vanderbilt pseudopotentials [33], especially designed to work with a... 

We employed density functional calculations using the ultrasoft pseudopotential plane wave method to investigate the CHQ nanotubes and the encapsulated silver nanowires. The local density approximation (LDA) of Ceperley and Alder and Vanderbilt pseudopotential was employed and the cutoff energy of the plane wave basis set was 20 Ry [27,182-185]. Full-potential linearized augmented plane wave method calculations were also carried out on the isolated silver nanowire [195-197]. To check the reliability of our... 

Calculations used the CASTEP code with a plane-wave basis set ( cutofr= 340 eV) and Vanderbilt-type ultrasoft pseudopotentials. The surface model as well as the -point mesh was as described in Section IV. 1.//. 

K. Laasonen, A. Pasquarello, R. Car, C. Lee, and D. Vanderbilt, Car-Parrinello molecular dynamics with Vanderbilt ultrasoft pseudopotentials, Phys. Rev. B Condens. Matter, 47 (1993), 10142-10153. 

We have performed ground state total-energy calculations using the pseudopotential plane-wave method based on density-functional theory in the local density approximation for exchange and correlationThe Vanderbilt ultrasoft pseudopotentials were used ... 

An ultrasoft type of pseudopotential was introduced by Vanderbilt (1990) and Laasonen et al. [1993] to deal with nodeless valence states which are strongly localized in the core region. In this scheme the normconserving condition is lifted and only a small portion of the electron density inside the cutoff radius is recovered by the pseudo-wavefunction, the remainder is added in the form of so-called augmentation charges. Complications arising from this scheme are the nonorthogonality of Kohn-Sham orbitals, the density dependence of the nonlocal pseudopotential, and need to evaluate additional terms in atomic force calculations. 

---