Bond-forming and electron-transfer reactivity between Ar²⁺ and N₂

Area of Science:

• Atomic and Molecular Physics
• Chemical Physics
• Collision Dynamics

Background:

• Understanding ion-molecule reactions is crucial for plasma physics and astrochemistry.
• Previous studies have explored Ar-N2 interactions, but detailed dynamics at specific collision energies are less understood.

Purpose of the Study:

• To investigate the reaction dynamics of Ar2+ colliding with N2 at a center-of-mass energy of 5.1 eV.
• To identify and characterize the different reaction channels and their underlying mechanisms.

Main Methods:

• Coincidence technique was employed to study the Ar2+ + N2 collisions.
• Analysis of scattering angles and energy transfer provided insights into reaction pathways.

Main Results:

• Four monocations channels were observed: Ar+ + N2+, Ar+ + N+, ArN+ + N+, and N+ + N+.
• The Ar+ + N2+ channel, primarily forming ground-state Ar+ and vibrationally excited N2+, dominated the reaction, suggesting competing direct electron transfer and complex-assisted collisions.
• Dissociative single electron transfer leading to Ar+ + N+ involved excited Ar2+ states and dissociative N2+ states.
• ArN+ + N+ formation occurred via a direct mechanism, producing vibrationally excited ArN+.
• Double electron transfer resulted in N+ + N+ formation, populating specific dication states of N2.

Conclusions:

• The collision dynamics of Ar2+ and N2 are complex, involving multiple competing mechanisms.
• Both direct and complex-assisted electron transfer pathways play significant roles in the observed reaction channels.
• The study provides detailed insights into the state-selective dynamics of these ion-molecule collisions.