"Compressional, temporal, and compositional behavior of H2-O2 compound formed by high pressure x-ray irradiation"

Andrew Kung: Alexander F. Goncharov, Chang sheng Zha, Peter Eng, and Wendy L. Mao; J. Chem. Phys., 06/15/11.

Additional Authors: Alexander F. Goncharov, Chang sheng Zha, Peter Eng, and Wendy L. Mao

Abstract:

X-ray irradiation was found to convert H2O at pressures above 2 GPa into a novel molecular H2-O2 compound. We used optical Raman spectroscopy to explore the behavior of x-ray irradiated H2O samples as a function of pressure, time, and composition. The compound was found to be stable over a period of two years, as long as high pressure conditions (>2 GPa) were maintained. The Raman shifts for the H2 and O2 vibrons behaved differently from pure H2 and O2 as pressure was increased on the compound up to 70 GPa, indicating that it remains a distinct, molecular compound. Based on spectra taken from different locations in a single sample, it appears that multiple forms of the H2-O2 compound exist. The structure and composition of the starting material plays an important role in compound formation, as we found that hydrogen-filled ice clathrate C2 (H2)H2O did not undergo the same dissociation as observed in ice VII upon x-ray irradiation until pressure was increased to above 10 GPa