  Full magnetization process of magnetic nanocluster Mn4, including all its
actual multiplets, is theoretically investigated. The formulas needed to
determine the exchange constants of cluster Mn4 from experimental data are
obtained. It is shown that quantum jumps of magnetization of this nanocluster
are in area of megagauss magnetic fields. Remarkable feature of considered
nanocluster Mn4 differing it from other multispin molecules is that its
exchange spin Hamiltonian supposes exact diagonalization. This provides a
reliable basis for comparison of theoretical predictions with experimental data
and is important for development of new experimental techniques of high-spin
molecule research.
