1. Select atom type & click on the crystal canvas to add it.
2. Adjust controls to see their effect on the pattern. The spot area is proportional to the intensity (other scales are available below).
3. The calculations are made in P-type cell, some shallow points might appear due to rounding errors.
Every atom's amplitude is multiplied by exp(−B·s²), with s = sinθ/λ. B adds two effects: the finite size of the atom (form factor f(s) ≈ f0·exp(−Bfs²)) and the thermal motion (Debye–Waller, BT = 8π²⟨u²⟩): B = Bf + BT. B = 0 gives point atoms with a constant f.