Structural Evidence for the Spin Collapse in High Pressure Solid Oxygen
Year: 2025
Authors: Gorelli F.A., Dalladay-Simpson P., Garbarino G., Mezouar M., Haines J., Santoro M.
Autors Affiliation: Shanghai Adv Res Phys Sci SHARPS, Shanghai, Peoples R China; Ctr High Pressure Sci & Technol Adv Res, 1690 Cailun Rd, Shanghai 201203, Peoples R China; Consiglio Nazl Ric CNR, Ist Nazl Ott, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy; European Lab Non Lnear Spect LENS, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy; European Synchrotron Radiat Facil, 71 Ave Martyrs, F-38000 Grenoble, France; Univ Montpellier, Inst Charles Gerhardt Montpellier ICGM, CNRS, ENSCM, F-34293 Montpellier, France.
Abstract: Single crystal x-ray diffraction measurements have been carried out on epsilon oxygen up to 30 GPa to examine the behavior of the constituent (O2)4 units. An isostructural phase transition is evidenced by lattice parameter and intracluster (O8) distance discontinuities and clear changes in the equation of state at 18.1 + 0.5 GPa on compression. This transition corresponds well to the predicted collapse of the molecular magnetic moment from spin-liquid, e1, to a spinless, e0, states of the O8 structure. The collapse of the molecular magnetic moment has to date only been supported by spectroscopic data and, until now, has not been substantiated structurally.
Journal/Review: PHYSICAL REVIEW LETTERS
Volume: 135 (7) Pages from: 76101-1 to: 76101-7
More Information: We acknowledge the European Synchrotron Radiation Facility for provision of beam time at ID27 (proposal CH-5607 and CH-6300). M. S. acknowledges HPSTAR for having allowed him as a Visiting Scientist during part of his research on solid oxygen.KeyWords: Epsilon-phase; Metallization; TransitionDOI: 10.1103/jvd7-v9h9
