Charge-density-wave satellite intensity in potassium

The intensity of a charge-density-wave diffraction satellite in potassium is calculated. Velocity dependence of the exchange and correlation potential, which is responsible for the conduction-electron charge modulation, significantly affects the deduced value of the charge-density-wave amplitude. The amplitude of the periodic lattice displacement, which screens the electronic modulation, is reduced to a very small value, 0.03 Å, when the real charge distribution of a positive ion is recognized. A random $\overrightarrow{\mathrm{Q}}$-domain structure can lead to a reduction by a factor of 24, compared to a single-$\overrightarrow{\mathrm{Q}}$ specimen, of the satellite intensity. In such a case it is only 1.4×${10}^{-5\mathrm{}}$ that of a crystallographic Bragg reflection. At temperatures above liquid helium, satellite intensity may be reduced further by phason excitations.