[en] Ground rotational bands of most deformed even-even nuclei with mass A ≥ 100 up to the rotational energy ε(J) ≤ 5 MeV can be fitted by empirical formula ε_N(J)=ε₀sin²(π|J|/N) with ε₀ ≅ 6.7 MeV and with one fitting parameter N, close to the charge of the nucleus Z. It is proposed to interpret a rotational state of the deformed nucleus as a state with conserved orientation of the axis of symmetry directed along the conserved projection of the angular momentum. Arguments are given in favor of the assumption that collective 'rotational' momentum is created by circular tunnel current of pairs of correlated nucleons. 11 refs., 12 tabs