3.2衍射产生的条件 3.2.1几何条件 It is worthy to point out that (nh,nk,nl)planes are here named as interference planes which is distinguished from Miller index planes.For example,(100)planes in interference planes are different from(200),since the spacings or the normal direction of their planes are different,however,these planes in Miller index planes all belong to {100}plane family and are not discriminated. Another physical concept is that interference planes may not correspond to a real interatomic plane.For example, in simple cubic lattice,no any lattice points (atoms,or molecules)exist in (200)planes.Based on the concept mentioned above,Bragg equation can be rewritten as a form of the first order diffraction: 2dnk sin=A3.2 衍射产生的条件 3.2.1 几何条件 It is worthy to point out that (nh,nk,nl) planes are here named as interference planes which is distinguished from Miller index planes. For example, (100) planes in interference planes are different from (200), since the spacings or the normal direction of their planes are different, however, these planes in Miller index planes all belong to {100} plane family and are not discriminated. Another physical concept is that interference planes may not correspond to a real interatomic plane. For example, in simple cubic lattice, no any lattice points (atoms, or molecules) exist in (200) planes. Based on the concept mentioned above, Bragg equation can be rewritten as a form of the first order diffraction: 2dhklsin  