Quantum indistinguishability in chemical reactions

Area of Science:

• Quantum Chemistry
• Chemical Physics
• Biophysics

Background:

• Quantum indistinguishability is fundamental in low-energy physics but often neglected in high-temperature chemical processes.
• Ionic coordinates in high-temperature reactions are typically treated as distinguishable and classical, ignoring quantum effects.

Purpose of the Study:

• To investigate the role of quantum mechanics in enzymatic chemical reactions involving small symmetric molecules.
• To propose a "quantum dynamical selection" (QDS) rule governing these reactions.

Main Methods:

• Exploration of enzymatic reactions with small symmetric molecules.
• Application of physical arguments to support the proposed QDS rule.
• Theoretical analysis of collective nuclear degrees of freedom.

Main Results:

• Conjecture of the QDS rule, which restricts chemical processes involving transitions from orbitally nonsymmetric molecular states.
• Demonstration of QDS rule implications: differential reactivity of hydrogen isotopes, nuclear spin entanglement, mass-independent isotope fractionation.
• Explanation of enhanced reactivity of reactive oxygen species and the role of ortho-water in liquid water dynamics.

Conclusions:

• A full quantum treatment of nuclear degrees of freedom is essential for understanding many chemical reactions.
• The QDS rule provides a unifying framework for diverse quantum phenomena in chemistry and biology.
• The study links quantum mechanics to biochemical processes, including potential quantum brain mechanisms.