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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.