Parity-violating effects in asymmetric chemical reactions: A theoretical study on the CHFClBr molecule

A coupled Hartree-Fock procedure has been employed to estimate the parity-violating energy contribution due to electroweak interaction in the vicinity of the transition point of a chemical reaction path starting from achiral reagents and producing the chiral CHFClBr molecule. The calculations demonstrate that (i) the S enantiomer is a reaction product more stable than its mirror image by approximately 1x10(-17) hartree; (ii) in the transition state of the reaction, the chiral activated complex evolving toward the S-CHFClBr species is more stable, by approximately 2.3x10(-17) hartree, than the enantiomeric activated complex that would yield the R-CHFClBr species. These results suggest that kinetic effects at work during chemical syntheses of chiral molecules might be more significant than the different thermodynamical stability of the two mirror-image reaction products in determining the final configuration and to explain homochirality.