dzeta Function

public elemental function dzeta(a, c, qref, qmod)

derivative of charge scaling function w.r.t. charge

Arguments

Type IntentOptional Attributes Name
real(kind=wp), intent(in) :: a
real(kind=wp), intent(in) :: c
real(kind=wp), intent(in) :: qref
real(kind=wp), intent(in) :: qmod

Return Value real(kind=wp)


Source Code

elemental function dzeta(a, c, qref, qmod)
   real(wp), intent(in) :: a
   real(wp), intent(in) :: c
   real(wp), intent(in) :: qref
   real(wp), intent(in) :: qmod
   real(wp) :: dzeta

   intrinsic :: exp

   if (qmod < 0.0_wp) then
      dzeta = 0.0_wp
   else
      dzeta = - a * c * exp( c * ( 1.0_wp - qref/qmod ) ) &
         & * zeta(a,c,qref,qmod) * qref / ( qmod**2 )
   endif

end function dzeta