anchor.diff:  c     ***** revPBE GGA exchange constants ******
         real*8 MU,KAPPA
         parameter (MU    = 0.2195149727645171d0)
  -c      parameter (KAPPA = 0.8040000000000000d0)
  +      !parameter (KAPPA = 0.8040000000000000d0)
         parameter (KAPPA = 1.2450000000000000d0)
    
  -c     ****** PBE96 GGA correlation constants ******
  +c     ****** revPBE GGA correlation constants ******
         real*8 GAMMA,BETA,BOG
         parameter (GAMMA	= 0.031090690869655d0)
         parameter (BETA	= 0.066724550603149d0)
  
positive.code:          phi3 = phi**3
           phi4 = phi3*phi
           PON  = -ec_lda/(phi3*GAMMA)
           tau  = dexp(PON)
  
           A = BOG/(tau-1.0d0+ETA)
           A2 = A*A
  
negative.code: c     **** other constants ****
        real*8 onethird,fourthird,fivethird,onesixthm
        real*8 twothird,sevensixthm
        real*8 onethirdm
        parameter (onethird=1.0d0/3.0d0)
        parameter (onethirdm=-1.0d0/3.0d0)
        parameter (twothird=2.0d0/3.0d0)
  