2026-10-14T16:56:30Z https://api.figshare.com/v2/oai

oai:figshare.com:article/34028297 2026-09-30T00:05:27Z category_1 category_14 category_16 category_24 category_272 category_873 category_734 portal_63 item_type_6 month_year_09_2026

A High-Density Supercritical Fluid of H2 Atsuko Nakayama (790698) Naoto Fujii (7150790) Koji Hirama (25139576) Kentaro Hamada (14684601) Katsuya Shimizu (7475186) Yuki Nakamoto (3956867) Satoshi Nakano (655819) Saori Kawaguchi-Imada (17443043) Yuichi Akahama (25139579) Ayako Ohmura (25139582) Biophysics Molecular Biology Physiology Evolutionary Biology Environmental Sciences not elsewhere classified Chemical Sciences not elsewhere classified Biological Sciences not elsewhere classified supercritical fluid hydrogen molecular mechanisms rather density supercritical fluid centered cubic model using synchrotron radiation nearest neighboring h crossover occurs primarily 2 </ sub q </ study aimed structure factor structural evolution slight discrepancy scf h room temperature ray diffraction pressure using low -< internuclear distance intermolecular shortening increased gradually finding indicates densification following cited equation around 0 adequately explained 56 gpa This study aimed to elucidate the structural evolution of supercritical fluid hydrogen (SCF H2) under high pressure. X-ray diffraction was performed on SCF H2 using synchrotron radiation at room temperature. The structure factor S(Q) was observed in a low-Q region at each pressure, revealing a crossover at around 0.56 GPa, consistent with our previous Raman spectroscopy results. The average volume per molecule was calculated at each pressure using the center-to-center distance between the nearest neighboring H2 molecules, reflecting van der Waals interactions and compression of the internuclear distance. The volumes calculated from the face-centered cubic model were consistent with those derived from the cited equation of state, with a slight discrepancy that increased gradually with the pressure. This finding indicates that further densification following the crossover occurs primarily by intra-atomic/molecular mechanisms rather than intermolecular shortening of distances, which cannot be adequately explained by the close-packed coordination model alone. 2026-09-29T00:00:00Z Text Journal contribution 10.1021/acs.jpclett.6c02439.s001 https://figshare.com/articles/journal_contribution/A_High-Density_Supercritical_Fluid_of_H_sub_2_sub_/34028297 CC BY-NC 4.0