Dense, Subnano Phase of Clustered O-2
Authors: Santoro M., Dziubek K., Scelta D., Morana M., Gorelli FA., Bini R., Hanfland M., Rouquette J., di Renzo F., Haines J.
Autors Affiliation: CNR, INO, Ist Nazl Ott, I-50019 Sesto Fiorentino, Italy; European Lab Non Linear Spect LENS, I-50019 Sesto Fiorentino, Italy; CNR, ICCOM, Ist Chim Composti Organometallici, I-50019 Sesto Fiorentino, Italy; Univ Firenze, Dipartimento Chim, I-50019 Sesto Fiorentino, Italy; European Synchrotron Radiat Facil, F-38343 Grenoble, France; Univ Montpellier, CNRS, ENSCM, ICGM, F-34095 Montpellier, France; Univ Pavia, Dipartimento Sci Terra & Ambiente, I-27100 Pavia, Italy
Abstract: Condensed O-2 tends to form clusters, even with a long-range order. In particular, in solid oxygen, strong intermolecular charge transfer at high pressures leads to the formation of (O-2)(4) tetramers above 10 GPa, in the epsilon-O-2 phase, with weak O-2-O-2 chemical bonds. Indeed, epsilon-O-2 is entirely made of these tetramers. We conducted experimental investigations on strongly densified O-2 in a different environment, that is to say in the form of a subnano phase build up within the 1D microchannels of a purely siliceous, inert zeolite, TON, at pressures of 0.520 GPa, by means of diamond anvil cells. Our X-ray diffraction and infrared and Raman spectroscopy results consistently show that oxygen forms clusters in this nanophase, above 10 GPa, similar to epsilon-O-2, except that the clusters are rather of the type of weakly bonded (O-2)(2) dimers in this case. Also, by analogy with bulk oxygen, we show that the O-2 spin within the dimers departs from S = 1 toward lower values, upon increasing pressure. Our findings thereby add to the general view on essential properties of highly dense oxygen.
Journal/Review: JOURNAL OF PHYSICAL CHEMISTRY C
Volume: 123 (14) Pages from: 9651 to: 9657