#CO2 MOLECULAR GEOMETRY FREE#

This is one of well-known force fields that supplies reliable intramolecular force constants within the organic linker however it is not developed directly for the system of MOFs or ZIFs as in this study. There are some computer simulations where bonding and non-bonding parameters of general force fields such as AMBER are applied. Computer models and simulations can be used to rapidly screen and develop promising ZIFs with large savings in experimental time and cost.

The high-throughput methods can be successfully applied to the development a robust synthesis protocol for several ZIFs in short time. It is composed of Zn 2+ ion clusters linked by dipotic benzimidazolate ( −) ligands with chemical formula Zn 2 (see Figure 1). The ZIF-11 is one of ZIFs which exhibits the RHO topology. Some ZIFs are attracted as materials which are used to keep the emissions of CO 2 out of the atmosphere in hot energy-producing environments like power plants due to their exceptional chemical and thermal stabilities and nontoxic crystals. Zeolitic imidazolate frameworks (ZIFs) are subclass of MOFs, in which positive metal ions such as Zn, Co, and Cu are linked by ditopic imidazolate ligands.

Metal-organic frameworks (MOFs) are a class of nanoporous materials that are promising candidates for CO 2 capture, due to their potential applications in separation processes, catalysis, and gas storage. The low energy requirement technologies based on adsorption processes are highlighted as promising methods, stimulating recent works to investigate suitable adsorbent materials. The cost-effective and scalable technologies to capture and store CO 2 are now of great interest. Human activities such as combustion of fossil fuels (coal, oil, and natural gas) in power plants, automobiles, and industrial facilities are main sources of CO 2 emission. The increase in carbon dioxide (CO 2) in Earth’s atmosphere is a subject of worldwide attention as being the cause of global warming. Due to the limitations of computing resources and times in this study, the results of flexible framework simulation using refined nonbonding AMBER parameters (SIM IV) are not much different from those obtained in SIM II.

#CO2 MOLECULAR GEOMETRY FREE#

The Zn-Zn and Zn-N RDFs in free flexible framework simulation (SIM III) show validity of adapting AMBER bonding parameters. One slight but notable difference is that CO 2 molecules are mostly located around and closer to hydrogen atom of imidazolate ring in SIM II than those found in SIM I. The site-site radial distribution functions and the molecular distribution plots simulations indicate that all hydrogen atoms are favored binding site of CO 2 molecules. Molecular dynamics simulations of CO 2 molecules in rigid framework ZIF-11, have then been performed using original AMBER parameters (SIM I) and refined parameters (SIM II), respectively. The energy and geometry scaling factors are obtained to be 1.2 and 0.9 for and parameters, respectively. Nonbonding parameters of AMBER force field have been refined based on ab initio binding energies of CO 2– − complexes.

Co2 molecular geometry