Proton Transfer vs Complex Formation Channels in Ionized Formic Acid Dimer: A Direct Ab Initio Molecular Dynamics...

Area of Science:

• Physical Chemistry
• Chemical Dynamics
• Molecular Modeling

Background:

• Hydrogen-bonded systems are crucial in biological processes like DNA and enzyme damage.
• The formic acid dimer serves as a model for studying double proton transfer in systems like DNA base pairs.

Purpose of the Study:

• To investigate the reaction dynamics of the formic acid dimer cation using direct ab initio molecular dynamics.
• To identify and characterize the reaction channels and their temperature dependence.

Main Methods:

• Direct ab initio molecular dynamics simulations.
• Analysis of reaction channels: complex formation and proton transfer.
• Correlation of spin distribution with reaction pathways.

Main Results:

• Two primary reaction channels were identified for the formic acid dimer cation: complex formation and proton transfer.
• Complex formation, involving symmetric carbonyl oxygen bonding, dominates at low temperatures.
• Proton transfer increases with temperature, forming a specific radical cation product, and is correlated with asymmetric spin distribution.

Conclusions:

• The study elucidates the complex reaction dynamics of the formic acid dimer cation.
• Temperature is a critical factor controlling the competition between complex formation and proton transfer.
• Asymmetric spin distribution serves as an indicator for the proton transfer pathway in these systems.