2025/05/01 by Kundu, Narayan, Rana, Meenakshi, Ghosh, Aryya +1 · 1 citation
#Atomic and Molecular Clusters (physics.atm-clus) #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2505.00532
We present a kinematically complete study of dissociative electron attachment (DEA) in linear OCS molecules, focusing on how electrons resonantly attach and trigger dissociation. Near the Franck-Condon regime, DEA is dominated by molecular shape resonances, where transient OCS- states form with high vibrational amplitudes, spectroscopically evident as broad features in DEA cross-sections. As the electron beam energy increases from 5.5 to 6.0 eV, S- population shifts from lower to higher-energy highly dense bending vibrational states, reinforcing our findings on dipole-forbidden vibronic intensity borrowing. Our advanced potential energy curve calculations, employing the Equation-of-motion coupled cluster singles and doubles for electron attachment (EA-EOMCCSD) method, reveal that beyond the shape resonance, non-adiabatic resonant tunneling governs the avoided crossings, dynamically generating three mode-specific vibronic Feshbach resonances before complete dissociation into three distinct kinetic energy bands of S-. Our theoretical results probe most of the experimental observations quantitatively and qualitatively. These insights deepen our fundamental understanding of resonance-mediated dissociation in electron-molecule resonant scattering, with broader implications for quantum mechanics, plasma physics, vibrational revival, astrochemistry, and radiation damage research.