Check for Computational Convergence Issues: Sometimes, insufficient convergence in electronic structure calculations or inappropriate initial geometry can lead to unexpected bond breakage. Ensuring proper convergence settings and carefully checking the initial molecular configuration may help in addressing this issue. Suppose your ethanol molecule starts with an abnormally long O-H bond (1.5 Å or greater, whereas the typical O-H bond length is around 0.96 Å). During relaxation, VASP might "think" that breaking the O-H bond and forming an alkoxide ion (C₂H₅O⁻) is energetically favorable, leading to bond dissociation.

Steps to fix:

• Visualize the initial structure before running the calculation. Use visualization tools like VESTA or Avogadro to ensure the bond lengths and angles are reasonable.
• Optimize the structure separately in the gas phase first, ensuring that the O-H bond is within normal length (~0.96 Å).
• Gradually introduce solvent effects, starting from a well-relaxed structure in the gas phase and then switching to VASPsol with implicit solvent.