Molecule Displacement and Structural Adaptation in Simulation

Hello,

I simulated a molecular system in a box and removed its central region to accommodate another molecule, slightly larger than its radius. After placing this molecular mass at the center of the box and optimizing the geometry, I observed that it shifted toward the bottom of the box.

  1. What could be the reason for this shift?

  2. Doesn’t this movement cause atomic overlaps or steric clashes?