Interaction of peroxyformic acid with water molecules: a first-principles study

Area of Science:

• Computational Chemistry
• Molecular Modeling
• Physical Chemistry

Background:

• Peroxyformic acid (PFA) is an important but unstable peroxyacid.
• Understanding its hydration is crucial for its stability and reactivity.
• Previous studies have not fully explored the cooperative effects of water in PFA clusters.

Purpose of the Study:

• To investigate the structures and energetics of peroxyformic acid (PFA) and its hydrated clusters (PFA·(H2O)n, n=1-4).
• To analyze the impact of water molecule addition on PFA's structural and vibrational properties.
• To quantify the cooperative hydrogen bonding interactions within these clusters.

Main Methods:

• Ab initio quantum chemical calculations using restricted Hartree-Fock (RHF) and MP2 methods.
• Employing 6-31G(d,p) and 6-311++G(2d,2p) basis sets for high accuracy.
• Detailed many-body interaction energy analysis to assess hydrogen bond cooperativity.

Main Results:

• Identified lowest energy conformers for PFA and its hydrated forms.
• Observed significant structural modifications and shifts in vibrational frequencies of PFA upon hydration.
• Quantified the cooperative enhancement of hydrogen bonding with increasing water molecules.

Conclusions:

• Hydration stabilizes peroxyformic acid through cooperative hydrogen bonding.
• The study provides a detailed molecular-level understanding of PFA-water interactions.
• Findings are relevant for predicting PFA behavior in aqueous environments.