Crystal nucleation in glass-forming liquids: Variation of the size of the structural units with temperature

The description of crystal nucleation rates in supercooled liquids in the framework of the classical nucleation theory (CNT) fails if one uses a fixed size of structural units. To reconcile the experimental data and CNT, we assumed an increase of the size of the structural units that control nucleation with decreasing temperature for temperatures below the nucleation rate maximum, T