anchor.diff:           PASS1  = .False.
   
         END IF
  +
  +! darothen: error checking on shell/core refractive indices
  +      ! print *, "   rindsh", rindsh
  +      ! print *, "    rcore", rindco
  +      ! print *, "==================================================="
  +
   
         XSHELL = RSHELL*WVNO
         XCORE  = RCORE*WVNO
  
positive.code:     wvnr = 2d0 * Pi / wavelength
  
      !refractive indices
      refr_shell = shell_refr
      refr_core = core_refr
  
      !shell/core radius [um]
      rshell = radius_shell
      rcore  = radius_core
  
  
      !get Mie coefficients for a sulfate coated BC particle with core 
      !radius r_core and shell radius rshell
  
negative.code:         radius_core,     &  ! core radius [um]
          wavelength          ! radiation wavelngth 
       
       complex (kind=ckind), intent(in) :: & 
          shell_refr,      &  ! shell refractive index
          core_refr           ! core  refractive index 
  
  