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The ab initio calculation have been performed on the addition of LiH to acetylene at RHF/3-21G basis set. The geometries and energies of the isolated reactant. molecular complex. transitionstate and product have been determined on the singlet potential energy surface of the ground state.Our results indicate that there is a meta-stable molecular complex near the isolated reactant in thereaction pathway. The process from isolated reactant to molecular complex is a non-bonding-ex-changing reaction process, and the process from molecular complex to product is the rate-controllingstep of the reaction. We also estimate the activated entropy and the frequency factor of the rate-controlling step by using the RRKM theory. The FMO analysis for the transition state reveals theHOMO of transition state to be formed from both HOMO-LUMO and HOMO-HOMO interactions.
The ab initio calculation have been performed on the addition of LiH to acetylene at RHF / 3-21G basis set. The geometries and energies of the isolated reactant. Molecular complex. Transitionstate and product have been determined on the singlet potential energy surface of the ground state.Our results that that there is a meta-stable molecular complex near the isolated reactant in thereaction pathway. The process from isolated reactant to molecular complex is a non-bonding-ex-changing reaction process, and the process from molecular complex to product is the rate-controllingstep of the reaction. We also estimate the activated entropy and the frequency factor of the rate-controlling step by using the RRKM theory. The FMO analysis for the transition state reveals the HOMO of transition state to be formed from both HOMO- LUMO and HOMO-HOMO interactions.