Predicting Coulomb explosion fragment angular distributions using molecular ground-state vibrational motion

Laser-induced Coulomb explosions can be used to identify gas-phase molecular structures through correlations betweenfragment ion trajectories. This report presents a model for predicting these outcomes, which first establishes the neutralequilibrium geometry of a target molecule using electronic structure calculations, and then samples a probability distributionof potential ground-state configurations by allowing for zero-point vibrational motion. Candidate structuresare assumed to explode instantaneously into charged fragments, and the simulated ion trajectories are correlated usingrecoil-frame covariance analysis. The effects of detection efficiency and fluctuating experimental conditions are alsoconsidered. The results were found to match experimental data, indicating that Coulomb explosion fragment angulardistributions produced from highly-charged ions depend largely on the internal motion of the target molecule