Cost-Effective Implementation of Multiconformer Transition State Theory for Peroxy Radical Hydrogen Shift Reactions.

摘要: Based on a small test system, (R)-CH(OH)(OO·)CH2CHO, we have developed cost-effective approach to the practical implementation of multiconformer transition state theory for peroxy radical hydrogen shift reactions at atmospherically relevant temperatures. While conformer searching is crucial accurate reaction rates, an energy cutoff can be used significantly reduce computational cost with little loss accuracy. For barrier, high-level calculations are needed, but highest level electronic structure not necessary relative between conformers. Improving both and decreases calculated rate significantly, so low-level rule out slow reactions. Further time saved by approximating tunneling coefficients each only that lowest-energy state. Finally, validate our usi...