Quantifying electron correlation effects in ethanol decomposition pathways

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Theoretical Chemistry

Background:

• Ethanol decomposition is a key multichannel organic reaction.
• Electron correlation significantly influences activation barriers and reaction selectivity.
• Accurate theoretical methods are needed to model these complex processes.

Purpose of the Study:

• To investigate ethanol decomposition pathways using fixed-node diffusion Monte Carlo (FN-DMC).
• To compare FN-DMC results with other computational methods and experimental data.
• To elucidate the role of electron correlation in reaction mechanisms.

Main Methods:

• Fixed-node diffusion Monte Carlo (FN-DMC) calculations.
• Investigation of three primary decomposition pathways: dehydration, C-C bond cleavage, and H2 elimination.
• Comparison with Hartree-Fock (HF), B3LYP, G2 theory, and experimental kinetic data.

Main Results:

• FN-DMC lowers HF activation barriers by 4-15 kcal mol-1, aligning with experimental data.
• Pathway-dependent modulation of dynamical correlation was observed near transition states.
• Dehydration channel showed the largest stabilization due to electron correlation.

Conclusions:

• FN-DMC provides a robust and accurate description of activation barriers in ethanol decomposition.
• The study offers mechanistic insights into electron correlation effects during bond-breaking reactions.
• FN-DMC is a valuable tool for studying complex chemical reactions.