Confinement-Driven Transient Coordination Complexes: H2 Dissociation and Quantum Channel Modification in Single-Atom Contacts
- 1ESIT – School of Engineering and Technology
- 2International University of La Rioja (UNIR
Abstract
Understanding chemical reactivity at cryogenic temperatures is essential for advancing both fundamental quantum science and next-generation catalytic technologies. At the single-atom limit, geometric confinement can promote ground-state electronic effects that drive novel chemical events without thermal activation. Using the H2 interaction with transition-metal nanocontacts as a benchmark, we report the barrierless formation of a transient tip complex characterized by a diborane-like 4-electron, 3-center bond (Pt–H ~0.17 and 0.18 nm). This 2 ground-state dissociation acts as a selective quantum channel modifier: while the intact, physisorbed molecule yields a conductance of ~0.2 G0, the dissociated transient complex results in a quantized conductance of 1 G0. This mechanism is correctly captured by mean-field orbital models when proper non-local exchange corrections are effectively considered. Furthermore, while bulk palladium is renowned for its high hydrogen affinity, our mean-field models and quantum calculations demonstrate the opposite: Pd nanocontacts merely physisorb H2 (H–H ~0.08 nm), behaving as a noble metal at this quantum limit. These findings illustrate how geometric confinement can drive novel chemical events, opening new avenues for zerotemperature catalysis at the single-atom limit.
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BibTeX
@misc{garcia2026confinementdriven,
title = {{Confinement-Driven Transient Coordination Complexes: H2 Dissociation and Quantum Channel Modification in Single-Atom Contacts}},
author = {Yamila García and Yamila Garcia-Martinez},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009624/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009624/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Confinement-Driven Transient Coordination Complexes: H2 Dissociation and Quantum Channel Modification in Single-Atom Contacts
AU - Yamila García
AU - Yamila Garcia-Martinez
PY - 2026
DA - 2026/09/29
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009624/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009624/v1
AB - Understanding chemical reactivity at cryogenic temperatures is essential for advancing both fundamental quantum science and next-generation catalytic technologies. At the single-atom limit, geometric confinement can promote ground-state electronic effects that drive novel chemical events without thermal activation. Using the H2 interaction with transition-metal nanocontacts as a benchmark, we report the barrierless formation of a transient tip complex characterized by a diborane-like 4-electron, 3-center bond (Pt–H ~0.17 and 0.18 nm). This 2 ground-state dissociation acts as a selective quantum channel modifier: while the intact, physisorbed molecule yields a conductance of ~0.2 G0, the dissociated transient complex results in a quantized conductance of 1 G0. This mechanism is correctly captured by mean-field orbital models when proper non-local exchange corrections are effectively considered. Furthermore, while bulk palladium is renowned for its high hydrogen affinity, our mean-field models and quantum calculations demonstrate the opposite: Pd nanocontacts merely physisorb H2 (H–H ~0.08 nm), behaving as a noble metal at this quantum limit. These findings illustrate how geometric confinement can drive novel chemical events, opening new avenues for zerotemperature catalysis at the single-atom limit.
ER -