Knowing the peak heights for the various expected peaks can be very useful in matching the observed peaks with the expected peaks. The height of the Patterson map origin peak is calculated:

• HO = z₁*z₁ + z₂*z₂ + ..... + z_n*z_n

where z_i is the atomic number of the i-th atom, and the summation is over the n atoms in the unit cell.

Patterson maps are frequently scaled such that the largest peak (the origin peak) takes a value such as "999". The scale factor relating the calculated peak heights to the observed peak heights would then be:

• SF = 999 / HO

Then, the expected peak height in the scaled Patterson map for a single-weighted (multiplicity = 1) vector between atoms of atomic numbers z_i and z_j would be:

• z_i * z_j * SF

Example:

1. molecule (formula unit) contains: C₆H₁₈F₂N₁₀NiO
2. unit cell contains four molecules (Z = 4)

Origin peak:

      zi   zi   ni   Z
  Ni  28 * 28 *  1 * 4  =  3136.
  F2   9 *  9 *  2 * 4  =   648.
  O    8 *  8 *  1 * 4  =   256.
  N10  7 *  7 * 10 * 4  =  1960.
  C6   6 *  6 *  6 * 4  =   864.
  H18  1 *  1 * 18 * 4  =    72.
                           -----
                    HO  =  6936.

Scale factor:

  SF = 999. / 6936. = 0.144

Expected peak heights:

           zi   zj
  Ni - Ni  28 * 28 * SF  = 112.9  (multiplicity = 1)
                           225.8  (multiplicity = 2)
                           451.7  (multiplicity = 4)

  Ni - F   28 *  9 * SF  =  36.3  (multiplicity = 1)
                            72.6  (multiplicity = 2)
                           145.2  (multiplicity = 4)

  F  - F    9 *  9 * SF  =  11.7  (multiplicity = 1)
                            23.3  (multiplicity = 2)
                            46.7  (multiplicity = 4)

  (etc.)

If the space group were #14, b-axis unique, 2nd cell choice (P2₁/n) then the expected Patterson map peaks and their scaled heights would be:

                                      0, 0, 0   999.
                              2X, 1/2, 1/2+2Z   226.
                             1/2, 1/2+2Y, 1/2   226.
                                   2X, 2Y, 2Z   113.
                               (etc.)