Electron attachment to PSCl3.

Area of Science:

• Physical Chemistry
• Chemical Physics
• Gas-Phase Ion Chemistry

Background:

• Electron attachment is a fundamental process in chemistry.
• Understanding electron attachment to molecules like PSCl3 provides insights into reaction mechanisms and ion formation.

Purpose of the Study:

• To investigate electron attachment to PSCl3 under varying pressure and temperature conditions.
• To determine rate constants, branching fractions, and identify ion products.
• To elucidate the role of electron affinity and molecular structure in attachment processes.

Main Methods:

• Flowing-afterglow Langmuir-probe (FALP) apparatus for low-pressure studies (133 Pa He, 298–550 K).
• Ion mobility mass spectrometry for high-pressure studies (9–93 kPa N2, 298 K).
• Gaussian-3 (G3) theoretical calculations for electronic structure and properties.

Main Results:

• A near-constant electron attachment rate constant of 5.1 x 10⁻⁸ cm³ s⁻¹ was observed between 298–550 K.
• At low pressures, only dissociative products (PSCl2⁻ and Cl⁻) were observed, with a suggested activation energy for PSCl2⁻ formation.
• At high pressures, the parent anion (PSCl3⁻) channel became significant, increasing with N2 pressure.
• Theoretical calculations indicated EA(PSCl2) < EA(Cl), explaining low-pressure branching, and EA(POCl2) > EA(Cl) for a related compound.

Conclusions:

• Electron attachment to PSCl3 exhibits pressure-dependent product distributions.
• The electron affinity of fragment anions plays a crucial role in dissociative attachment pathways.
• Theoretical calculations support experimental observations and provide deeper mechanistic understanding.