The potential of mean force (PMF) was computed from the RDF g(r) through the relationship F (r) = -k B T (ln g(r) -ln g max ), where g max is the maximum of g(r) over r. The N-Zn-N angle distribution and Zn-N coordination numbers are computed by taking a cutoff radius of 2.5 Å for Zn-N distances, a value determined based on the Zn-N PMF, and validated in previous ab initio and ReaxFF 15 studies. The total pore volume is computed on individual frames using the Zeo++ software, as the sum of accessible and non-accessible volume with a helium probe of radius 1.2 Å.