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arXiv · 2609.07324

Strong Evidence for Formation of Hydroxyl Anion via 2-Particle-1-Hole Feshbach Resonances

Siddique Ali·Meenakshi Rana·Soumya Ghosh·Narayan Kundu·Aryya Ghosh·Dhananjay Nandi
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Abstract

This study investigates the formation of the hydroxyl anion (OH$^-$) via dissociative electron attachment in 2-propanol as a model system for studying both organic and inorganic molecules. Using high-level CAP-EOM-EA-CCSD calculations and advanced ToF mass spectrometry, we demonstrate that OH$^-$ formation at electron energies between 7 and 11 eV is dominated by two-particle-one-hole (2p-1h) Feshbach resonances. The potential-energy curves reveal a dense manifold of anionic states coupled through numerous avoided crossings, facilitating nonadiabatic population transfer during C-OH bond dissociation. Survival-probability analysis identifies a subset of six long-lived resonances that persist long enough to drive fragmentation, with states 25 and 28 acting as primary drivers by funneling the attached electron into the localized $σ^*(\mathrm{C{-}OH})$ antibonding orbital. These theoretical predictions are confirmed by experimental observations of a prominent OH$^-$ yield peaking at 8.6 eV, supporting a site-specific fragmentation mechanism that generalizes to the broader class of molecules.

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Siddique Ali, Meenakshi Rana, Soumya Ghosh, Narayan Kundu, Aryya Ghosh, Dhananjay Nandi. 2026-09-07. Strong Evidence for Formation of Hydroxyl Anion via 2-Particle-1-Hole Feshbach Resonances. https://arxiv.org/abs/2609.07324

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