Molecular dynamics simulations with enhanced sampling were used to compute the free energy surface of the reactive adsorption of CO 2 in liquid ammonia. In enhanced sampling, an external bias potential acts on a system and allows the exploration of rarely-visited but physically-relevant regions in configurational space. This bias potential was constructed onthe-fly with Well-Tempered Metadynamics (WTMetad) and it allowed the sampling of all four states of interest: unbound CO 2 , H 3 N-CO 2 zwitterion, H 2 N-CO 2 H (carbamic acid) and H 2 N-CO - 2 (carbamate). All molecular dynamics (MD) simulations using DPMD were performed with the Lammps code interfaced with DeepMD-kit and Plumed. Free energy surfaces were averaged over 9 independent WTMetad simulations, each starting from different initial conditions. A total of 4.7 million WTMetad steps were accumulated using a timestep of 1 fs. WTMetad was performed with a bias factor of 20, initial Gaussian height 1.0 and 0.1 spread. Temperature was controlled with a 3-beads Nosé-Hoover thermostat chain. Pressure was kept at 1 bar using the Parrinello-Rahman barostat. Simulations of CO 2 in liquid NH 3 were performed in a system containing 2051 atoms (512 NH 3 and one CO 2 ) periodically repeated in a cubic unit cell with 28.9 Å edge length.