This work optimizes the link bond description of the quantum mechanical/molecular mechanical separation of deoxynucleosides. The nucleosides are separated at the C-N bond between the nucleobase and the deoxyribose, with the former acting as the quantum mechanically described species. By using a flexible link atom-ansatz plus a harmonic potential to correct the energy deviation from a full quantum mechanical description, the potential energy well of the bond’s stretching motion is mimicked with very high accuracy.