More Like this

1. Mechanisms of Complete Dissociation of CO ₂ on Iron Clusters

   https://doi.org/10.1002/cphc.202200277  

   Gutsev, Gennady_L; Tibbetts, Katharine_M; Gutsev, Lavrenty_G; Aldoshin, Sergey_M; Ramachandran, Bala_R (August 2022, ChemPhysChem)

   Abstract Dissociation of CO₂on iron clusters was studied by using semilocal density functional theory and basis sets of triple‐zeta quality. Fe₂, Fe₄, and Fe₁₆clusters were selected as the representative host clusters. When searching for isomers of Fe_nCO₂,n=2, 4 and 16 corresponding to carbon dioxide attachment to the host clusters, its reduction to O and CO, and to the complete dissociation, it was found that the total spin magnetic moments of the lowest energy states of the isomers are often quenched with respect to those of initial reagents Fe_n+CO₂. Dissociation pathways of the Fe₂+CO₂, Fe₄+CO₂, and Fe₁₆+CO₂reactions contain several transition states separated by the local minima states; therefore, a natural question is where do the spin flips occur? Since lifetimes of magnetically excited states were shown to be of the order of 100 fs, the search for the CO₂dissociation pathways was performed under the assumption that magnetic deexcitation may occur at the intermediate local minima. Two dissociation pathways were obtained for each Fe_n+CO₂reaction using the gradient‐based methods. It was found that the Fe₂+CO₂reaction is endothermic with respect to both reduction and complete dissociation of CO₂, whereas the Fe₄+CO₂and Fe₁₆+CO₂reactions are exothermic to both reduction and complete dissociation of carbon dioxide. The CO₂reduction was found to be more favorable than its complete dissociation in the Fe₄case. 

   more » « less
2. Dissociation Mechanism of a Single O ₂ Molecule Chemisorbed on Ag(110)

   https://doi.org/10.1021/acs.jpclett.1c02456  

   Lee, Minhui; Kazuma, Emiko; Zhang, Chi; Trenary, Michael; Takeya, Jun; Jung, Jaehoon; Kim, Yousoo (October 2021, The Journal of Physical Chemistry Letters)
3. Dynamics of “Hot” Oxygen Atoms on Ag(100) Surface upon O ₂ Dissociation

   https://doi.org/10.1021/acs.jpcc.3c05944  

   Gu, Kaixuan; Lin, Sen; Guo, Hua (November 2023, The Journal of Physical Chemistry C)
4. Density Functional Tight-Binding Captures Plasmon-Driven H ₂ Dissociation on Al Nanocrystals

   https://doi.org/10.1021/acs.jpcc.5c00805  

   Chellam, Nikhil S; Schatz, George C (May 2025, The Journal of Physical Chemistry C)

   Aluminum nanocrystals offer a promising platform for plasmonic photocatalysis, yet a detailed understanding of their electron dynamics and consequent photocatalytic performance has been challenging thus far due to computational limitations. Here, we employ density functional tight-binding methods (DFTB) to investigate the optical properties and H2 dissociation dynamics of Al nanocrystals with varying sizes and geometries. Our real-time simulations reveal that Al’s unique free-electron nature enables efficient light-matter interactions and rapid electronic thermalization. Cubic and octahedral nanocrystals ranging from 0.5 to 4.5 nm exhibit size-dependent plasmon resonances in the UV, with distinct spectral features arising from the particle geometry and electronic structure. By simulating H2 dissociation near Al nanocrystals, we demonstrate that hot electrons generated through plasmon excitation can overcome the molecule’s strong chemical bond within tens of femtoseconds. The laser intensity threshold is comparable to previous reports for Ag nanocrystals, though significantly lower than that of Au. Notably, the dipolar plasmon mode demonstrates higher efficiency for this reaction than the localized interband transition for particles at these sizes. Taken together, this work provides mechanistic insights into plasmon-driven catalysis and showcases DFTB’s capability to study quantum plasmonics at unprecedented length and time scales. 

   more » « less
5. Dissociation of Single O ₂ Molecules on Ag(110) by Electrons, Holes, and Localized Surface Plasmons

   https://doi.org/10.1002/tcr.202200011  

   Lee, Minhui; Kazuma, Emiko; Jung, Jaehoon; Trenary, Michael; Kim, Yousoo (March 2022, The Chemical Record)

   Abstract A detailed understanding of the dissociation of O₂molecules on metal surfaces induced by various excitation sources, electrons/holes, light, and localized surface plasmons, is crucial not only for controlling the reactivity of oxidation reactions but also for developing various oxidation catalysts. The necessity of mechanistic studies at the single‐molecule level is increasingly important for understanding interfacial interactions between O₂molecules and metal surfaces and to improve the reaction efficiency. We review single‐molecule studies of O₂dissociation on Ag(110) induced by various excitation sources using a scanning tunneling microscope (STM). The comprehensive studies based on the STM and density functional theory calculations provide fundamental insights into the excitation pathway for the dissociation reaction. 

   more » « less