Tunneling Effect in Proton Transfer: Transfer Matrix Approach

Area of Science:

• Chemical Physics
• Quantum Mechanics
• Computational Chemistry

Background:

• Proton transfer reactions are fundamental in chemical and biological processes.
• Accurate calculation of tunneling factors is crucial for understanding reaction rates.
• Existing methods may struggle with complex potential energy surfaces.

Purpose of the Study:

• To apply the transfer matrix (TM) method for calculating transmission probabilities (TPs) in proton transfer reactions.
• To evaluate tunneling factors using TPs derived from the TM method.
• To assess the TM method's accuracy and applicability to complex systems like DNA base pairs.

Main Methods:

• Utilized the transfer matrix (TM) method to compute transmission probabilities (TPs).
• Modeled Eckart potentials for guanine-cytosine base pairs to validate the TM method against analytical solutions.
• Applied the TM method to evaluate tunneling factors for guanine-thymine (G-T) and adenine-cytosine (A-C) mispair reactions.

Main Results:

• The TM method demonstrated high accuracy with minimal errors when compared to analytical solutions for guanine-cytosine base pairs.
• Significant tunneling contributions were observed for the G-T mispair reaction due to a shoulder in the potential.
• The A-C mispair reaction showed minimal tunneling contribution from the potential's shoulder.

Conclusions:

• The transfer matrix method is a reliable and accurate tool for calculating transmission probabilities and tunneling factors in proton transfer reactions.
• The TM method provides insights into tunneling phenomena in complex systems, surpassing limitations of methods like Wigner's tunneling factor.
• The study highlights differential tunneling contributions in DNA mispairs, with implications for understanding DNA stability and mutation.