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Abstract Borophenes have sparked considerable interest owing to their fascinating physical characteristics and diverse polymorphism. However, borophene nanoribbons (BNRs) with widths less than 2 nm have not been achieved. Herein, we report the experimental realization of supernarrow BNRs. Combining scanning tunneling microscopy imaging with density functional theory modeling and ab initio molecular dynamics simulations, we demonstrate that, under the applied growth conditions, boron atoms can penetrate the outermost layer of Au(111) and form BNRs composed of a pair of zigzag (2,2) boron rows. The BNRs have a width self‐contained to ∼1 nm and dipoles at the edges to keep them separated. They are embedded in the outermost Au layer and shielded on top by the evacuated Au atoms, free of the need for post‐passivation. Scanning tunneling spectroscopy reveals distinct edge states, primarily attributed to the localized spin at the BNRs’ zigzag edges. This work adds a new member to the boron material family and introduces a new physical feature to borophenes. 

A recent experiment at the Dalian Coherent Light Source (DCLS) has provided measurements of the partial cross sections for the photodissociation of water vapor over an unprecedented range of wavelengths in the vacuum ultraviolet (VUV) region. It was found that the three body dissociation channel, H + H + O( 3 P/ 1 D), becomes prominent at wavelengths shorter than the Lyman α-line at 121.6 nm. The present work explores the kinetic consequences of this discovery for several astrophysically motivated examples. The irradiation of a dilute low-temperature gas by unscreened solar radiation, similar to early stage photochemical processing in a comet coma, shows significant increase in the production of O 2 -molecules at shorter times, <1 day, that might physically correspond to the photochemical reaction zone of the coma. Several examples of planetary atmospheres show increased O-atom production at high altitudes but relatively little modification of the equilibrium O 2 concentrations predicted by conventional models. 

Abstract Despite major progress in the investigation of boron cluster anions, direct experimental study of neutral boron clusters remains a significant challenge because of the difficulty in size selection. Here we report a size‐specific study of the neutral B₉cluster using threshold photoionization with a tunable vacuum ultraviolet free electron laser. The ionization potential of B₉is measured to be 8.45±0.02 eV and it is found to have a heptagonal bipyramidD_7hstructure, quite different from the planar molecular wheel of the B₉^‐anionic cluster. Chemical bonding analyses reveal superior stability of the bipyramidal structure arising from delocalized σ and π bonding interactions within the B₇ring and between the B₇ring and the capping atoms. Photoionization of B₉breaks the single‐electron B‐B bond of the capping atoms, which undergo off‐axis distortion to enhance interactions with the B₇ring in the singlet ground state of B₉⁺. The single‐electron B‐B bond of the capping atoms appears to be crucial in stabilizing theD_7hstructure of B₉. This work opens avenues for direct size‐dependent experimental studies of a large variety of neutral boron clusters to explore the stepwise development of network structures.