Format of the pseudopotential files (US-vdb):
 (6i5)   six integers which identify the version of the pseudo. Put
         6 0 0 for the first three, the others are irrelevant
(a20,3f15.9)   line, zmesh(is), zp(is), exfact
(2i5,1pe19.11) nchi(is), mesh(is), etotpseu
(i5,2f15.9)    nnlz(nb), wwnl(nb), ee(nb), nb=1,nchi(is) 
(2i5,f15.9)    keyps, ifpcor, dummy
(2i5,f9.5,2i5,f9.5) lmax(is), lloc(is), eloc, ifqopt(is), nqf(is), dummy
(*)           (rinner(lp,is), lp=1,lmax(is)*2-1 )
(i5) irel
(1p4e19.11) rc(l), l=1,lmax(is) 
(2i5) nbeta(is), kkbeta(is)
      do nb=1,nbeta(is)
        (i5) lll(nb,is)
        (1p4e19.11) eee(nb),( betar(ir,nb,is), ir=1,kkbeta(is) )
         do mb=nb,nbeta(is)
           (1p4e19.11)  dion(nb,mb,is),  ddd(nb,mb), qqq(nb,mb,is),
     +           (qfunc(ir,nb,mb,is),ir=1,kkbeta(is)),
     +           ((qfcoef(i,lp,nb,mb,is),i=1,nqf(is)),lp=1,nqlc(is))
         enddo
      enddo
(1p4e19.11) rcloc, (vnl(ir,0,is), ir=1,mesh(is) )
if ( nlcc(is) ) then
   (1p4e19.11) ( rho_atc(ir,is), ir=1,mesh(is) )
endif

(1p4e19.11) (ru(ir), ir=1,mesh(is))
(1p4e19.11) (rho_at(ir,is), ir=1,mesh(is))
(1p4e19.11) (r(ir,is),ir=1,mesh(is))
(1p4e19.11) (rab(ir,is),ir=1,mesh(is))
(*)        ((chi(ir,nb,is),ir=1,mesh(is)),nb=1,nchi(is))


The allowed exfact are:
      0  LDA (Perdew and Zunger)
     -5 or 3  GGA (Becke-Perdew)
     -6 or 4  GGA (PW91)
           5  GGA (PBE)