説明:
(abstract)Surface melting of solidified hydrogen has attracted attention in the field of superfluidity, but the existence of surface melting of solid hydrogen itself is still controversial. In the present study, we developed cryogenic time-of-flight secondary mass spectrometry (ToF-SIMS) capable of detecting surface melting by selectively analyzing hydrogen on the outermost surface. Combined with low-energy ion scattering for well-defined film growth, we successfully investigated the surface structural transition of the quenched condensed hydrogen film grown on polycrystalline tungsten substrate below the triple point. It was found that the ToF-SIMS intensity variation of H$^+$ ions by increasing the temperature of the solid hydrogen film at a constant ramp rate (temperature-programmed ToF-SIMS) shows two prominent features: the increase accompanied by sublimation and the decrease due to the elimination of the hydrogen admolecule from the tungsten surface. Both features are well explained by the desorption of hydrogen molecules from the solid hydrogen surface. We observed no evidence of surface melting.
権利情報:
キーワード: Hydrogen, cryogenic TOF-SIMS
刊行年月日: 2024-08-22
出版者: American Physical Society (APS)
掲載誌:
研究助成金:
原稿種別: 著者最終稿 (Accepted manuscript)
MDR DOI: https://doi.org/10.48505/nims.5213
公開URL: https://doi.org/10.1103/physrevb.110.085426
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更新時刻: 2024-12-24 13:59:10 +0900
MDRでの公開時刻: 2024-12-25 08:30:42 +0900