The effect of Landau–Zener transitions on the $ac$-susceptibility

A model spin system $S=1$ with a strongly anisotropic $g$-factor is considered. Numerical calculations of the response of the system to an alternating magnetic field of low frequency are carried out. The influence of Landau–Zener transitions on the response of the system when it passes through the vicinity of the levels anti-crossing is studied. The $ac$-susceptibility is calculated and the effect of such transitions on the position of the $ac$-susceptibility maximum is analyzed.