Available pseudopotentials:
Becke-Lee-Yang-Parr (BLYP) exch-corr Martins-Troullier
Perdew-Burke-Ernzerhof (PBE) exch-corr nonlinear core-correction Vanderbilt ultrasoft
Perdew-Wang 91 gradient-corrected functional Martins-Troullier
Perdew-Zunger (LDA) exch-corr Bachelet-Hamann-Schlueter and derived