Nucleus-nucleus fusion energy thresholds and the adiabatic fusion potential

Experimental values of fusion energy thresholds, defined as energies at which the fusion cross section equals to the s-wave absorption cross section, are compared with barrier heights calculated assuming the adiabatic fusion potential with the nuclear part of the Woods-Saxon shape and parameters unambiguously determined by the liquid-drop-model contact force and the ground-state fusion Q value. Predictions of the ``capture'' cross sections in collisions of very heavy systems used to produce new superheavy elements are discussed.