The new model, which determines the active area (the region for which high-precision quantum methods must be used) of the
structure,was developed within the of the hybrid method (QM/MM). Problem of determining atoms with the critical tension values
is the basis of this model. The potential energy of these atoms and its nearest neighbours was calculated by quantum-chemical
method. The potential energy of the rest structure was calculated by molecular mechanical method. The Hybrid method (QM/MM)
