Electron-impact dissociation dynamics for modelling of plasma technologies

Electron-impact excitation plays a crucial role in dissociation processes in plasmas and hence determines the chemical composition as well as induced surface processes. Motivated by the search of new environmentally-friendly organofluorides for use in plasma technologies, we investigate electron-impact excitation and subsequent dissociation of C₃H₂F₄ and C₃H₂F₆. To investigate the dissociation dynamics in the time domain, we use the ab initio multiple cloning method [1], in which the nuclear motion of the excited molecule is described by an ensemble of Ehrenfest trajectories. To identify which states are strongly populated following electron-impact excitation, we calculate electron-impact excitation cross sections using the Quantemol Electron Collisions (QEC) code [2], that interfaces with the UKRmol+ suite of molecular R-matrix codes [3]. Using these approaches, we can identify the dominant dissociation pathways, and can predict the free radicals produced by electron-impact excitation. The results of the time-dependent calculations as well as the cross section data will be presented.

[1] D. Makhov et al., Chem. Phys. 493 200 (2017).

[2] B. Cooper et al., Atoms 7 97 (2019).

[3] Z. Masin et al., Comput. Phys. Commun. 249 107092 (2020).