anchor.diff:        real*8 alphac,malphac
         parameter (alphac=0.6001664769d0)
         parameter (malphac=1.0d0-alphac)
  -      real*8 a(0:29)
  -      data a(0:29)/1.516501714d0,  4.413532099d-1,-9.182135241d-2,
  +      real*8 am(0:29)
  +      data am(0:29)/1.516501714d0,  4.413532099d-1,-9.182135241d-2,
        >            -2.352754331d-2, 3.418828455d-2, 2.411870076d-3,
        >            -1.416381352d-2, 6.975895581d-4, 9.859205137d-3,
        >            -6.737855051d-3,-1.573330824d-3, 5.036146253d-3,
  
positive.code:          kf = (3.0d0*pi*pi*n)**onethird
           s  = agr/(2.0d0*kf*n)
  
           t    = 2.0d0*s*s/(4.0d0+s*s) - 1.0d0
           F    = 0.0d0
           Ft = 0.0d0
           s2   = t*t - 1.0d0
           if (dabs(s2).lt.1.0d-12) then
              do j=0,29
                 F  = F  + a(j)
                 Ft = Ft + a(j)*0.5d0*dble(j*(j+1))
              end do
           else
              oneovers2 = 1.0d0/s2
              p0 = 1.0d0
              dp = 0
              p1 = t
              dp = 1.0d0
              do j=2,29
                 p2    = (1.0d0/dble(j+1))*((2*j+1)*t*p1 - dble(j)*p0)
                 dp2   = dble(j)*oneovers2*(t*p2-p1)
                 F  = F + a(j)*p2
                 Ft = Ft + a(j)*dp2
                 p0 = p1
                 p1 = p2
              end do
  
negative.code:          ex   = ex_lda*F
           fnx  = fourthird*(ex - ex_lda*Fs*s)
           fdnx = fdnx_const*Fs
  
  
  *        *********************************************************************
  