Disclosing gate-opening/closing events inside a flexible metal-organic framework loaded with CO 2 by reactive and essential dynamics.

We have combined reactive molecular dynamics simulations with principal component analysis to provide a clearer view of the interactions and motion of the CO 2 molecules inside a metal-organic framework and the movements of the MOF components that regulate storage, adsorption, and diffusion of the guest species. The tens-of-nanometer size of the simulated model, the capability of the reactive force field tuned to reproduce the inorganic-organic material confidently, and the unconventional use of essential dynamics have effectively disclosed the gate-opening/closing phenomenon, possible coordinations of CO 2 at the metal centers, all the diffusion steps inside the MOF channels, the primary motions of the linkers, and the effects of their concerted rearrangements on local CO 2 relocations.