Abstract: The effects of temperature on the parity-violating entropy and energy differences of chiral molecules are investigated both theoretically and experimentally. Statistical thermodynamics calculations indicate the possible occur-rence of sign reversal of parity-violating entropy difference at different temperatures, which is supported by temperature-dependent polarized Raman spectra of D-alanine and L-alanine. An incoherent spontaneous symmetry breaking is proposed to describe the bifurcation mechanism between mirror-image systems at the critical temperature, in which usually violated parity symmetry will be dynamically restored again. An asymmetric double-well potential with a tiny parity-violating energy difference (PVED) in the depths of the two potential wells showed that the presence of PVED can lead to the enrichment of L-form amino acid. Tunneling dynamics of amino acids with PVED provides a plausible mechanism for much faster development of homochirality.

Key words: Temperature effect, Temperature-conformation-PVED relation, Parity-violating entropy difference, Tunneling dynamics, Alanine enantiomers