Whether the array of atoms is finite or infinite, one can also imagine an "intensity reciprocal lattice" I[ g ], which relates to the amplitude lattice F via the usual relation I = F F where F is the complex conjugate of F. Since Fourier transformation is reversible, of course, this act of conversion to intensity tosses out "all except 2nd moment" (i.e. the phase) information. For the case of an arbitrary collection of atoms, the intensity reciprocal lattice is therefore: