The HAlF4 superacid fragmentation induced by an excess electron attachment

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Physical Chemistry

Background:

• Superacid molecules possess unique electronic properties.
• Electron attachment can lead to complex molecular transformations.
• Understanding anion formation is crucial for reaction mechanisms.

Purpose of the Study:

• Investigate excess electron attachment to the HAlF4 superacid.
• Characterize the resulting anionic states and their stability.
• Elucidate the fragmentation pathway following electron attachment.

Main Methods:

• Ab initio coupled cluster singles doubles with triples (CCSD(T)) calculations.
• Møller–Plesset perturbation theory (MP2) methods.
• Augmented correlation-consistent basis set (aug-cc-pVTZ+4s4p3d).

Main Results:

• HAlF4 attracts an excess electron forming a dipole-bound anion with 1106 cm(-1) binding energy.
• The transient (HAlF4)(-) anion undergoes spontaneous rearrangement.
• Fragmentation into (AlF4)(-) superhalogen anion and a hydrogen atom occurs.
• Electron density migrates to the AlF4 moiety, stabilizing it in a near-tetrahedral geometry.

Conclusions:

• Excess electron attachment to HAlF4 is a multi-step process initiated by dipole-bound anion formation.
• The dipole-bound state acts as a transient intermediate, facilitating superhalogen anion formation and molecular fragmentation.
• The study predicts spontaneous dissociation of HAlF4 upon electron capture.