  By single-time reduction technique of Bethe-Salpeter formalism for
two-fermion systems analytical expressions for the quasipotential of
quark-quark interactions in QCD have been obtained in one-gluon exchange
approximation. The influence of infrared singularities of gluon Green`s
functions on the character of quark-quark forces in QCD has been investigated.
The way the asymptotic freedom manifests itself in terms of two-quark
interaction quasipotential in quantum chromodynamics is shown. Consistent
relativistic consideration of quark interaction problem by single-time
reduction technique in QFT allows one to establish a nontrivial energy
dependence of the two-quark interaction quasipotential. As a result of the
energy dependence of the interaction quasipotential, the character of the
forces changes qualitatively during the transition from the discrete spectrum
(the region of the negative values of the binding energy) to the continuous
spectrum (that of the positive values of the binding energy): the smooth
behaviour of the interaction quasipotential in the discrete spectrum goes into
the oscillation in the continuous spectrum. This result gives a visual physical
picture where the oscillations may be interpreted as a manifestation of a
quasicrystall structure of the vacuum.
