  A new measure of the crystal-field strength, complementary to the
conventional one, is defined. It is based on the rotational invariants
|B_{k0}|_{av} or |\sum_{k}B_{k0}|_{av}, k=2,4,6, of the crystal-(ligand)-field
(CF) Hamiltonian H_{CF} parametrizations, i.e. on the axial CF parameters
modules averaged over all reference frame orientations. They turn out to be
equal to |H_{CF}^{(k)}|_{av} and |H_{CF}|_{av}, respectively. While the
traditional measure is established on the parametrization modules or on the
second moment of the CF energy levels, the introduced scale employs rather the
first moment of the energy modules and has better resolving power. The new
scale is able to differentiate the strength of various iso-modular
parametrizations according to the classes of rotationally equivalent
parametrizations. Using both the compatible CF strength measures one may draw
more accurate conclusions about the Stark levels arrays and particularly their
total splitting magnitudes.
