A model in which the metal-hydrogen interatomic interaction potential in th
e solid phase is described by the Gauss normal distribution function was su
ggested to explain and predict equilibrium isotopic effects in hydrogen-int
ermetallic compound hydride systems. The quantum mechanical variational pri
nciple was used to parametrize the Gauss potentials for Group IV and V tran
sition metals in the approximation of local modes for hydrogen atom vibrati
ons. These potentials were transferred to intermetallic compounds with Lave
s phase structures. Calculations performed in a similar way gave the temper
ature dependences of separation coefficients for hydrogen isotopes that wer
e close to experimental for both stoichiometric and superstoichiometric for
ms of AB(2) compounds. These results prove the applicability of the represe
ntation of the potential for hydrogen in intermetallic compounds as a super
position of the potentials of separate metal atoms, which allows simple cri
teria for the search for systems with the largest isotopic effect to be for
mulated and substantiated.