Dissociative Electron Attachment in C2H via Electronic Resonances

Investigation of microwave-activated CH 4 /H 2 plasma used in chemical vapor deposition of diamond revealed the presence of electronically excited C 2 - (B 2 Σ u + ). Using high-level electronic structure methods, we investigate electronic structure of C 2 H - and suggest possible routes for formation of C 2 - in the ground (X 2 Σ g + ) and excited (B 2 Σ u + ) states via electronic resonances. To describe electronically meta-stable states, we employ the equation-of-motion coupled-cluster method augmented by the complex absorbing potential. The resonance wave-functions are analyzed using natural transition orbitals. We identified several resonances in C 2 H - , including the state that may lead to C 2 - (B 2 Σ u + ).