Reply to “Comment on ‘Synthesis and properties of selenium trihydride at high pressures’ ”
Reply to “Comment on ‘Synthesis and properties of selenium trihydride at high pressures’ ”
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DOI：
10.1103/physrevb.98.106102
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发表时间：
2018-09
影响因子：
3.7
通讯作者：
Xiao Zhang;Wan Xu;Yu Wang;Shu-qing Jiang;F. Gorelli;E. Greenberg;V. Prakapenka;A. Goncharov
中科院分区：
文献类型：
--
作者：
Xiao Zhang;Wan Xu;Yu Wang;Shu-qing Jiang;F. Gorelli;E. Greenberg;V. Prakapenka;A. Goncharov
The Comment of Pace et al. [Phys. Rev. B in press] claims that structural analysis and nomenclature of Zhang et al. [Phys. Rev. B 97, 064107 (2018)] is incorrect, that this compound is not metallic at high pressures and 200 K, and that the compound instead decomposes. In this Reply we argue that there are no experimental data that can discriminate between theoretically predicted Cccm H3Se and advocated by Pace et al. I4/mcm (H2Se)2H2. The difference in nomenclature is due to different naming conventions. We find the name “H3Se” more convenient to apply in the limit of high-pressure. We also substantiate the initial claims of the stability up to 40 GPa at 170 K of the H3Se compound after synthesis at 4.6 GPa and argue that the pressure induced metallization above 23 GPa is a plausible explanation of the reported visual observations and Raman spectroscopy results. Main text According to Pace et al. , Zhang et al. 2 claim that they synthesized a new compound H3Se which is different from the theoretically predicted one that was also synthesized under similar conditions by Pace et al. . The material synthesized by Zhang et al. 2 is clearly the same as theoretically predicted 3 and subsequently synthesized by Pace et al. ; this can be seen based on the presented x-ray diffraction (XRD) and Raman data. While we admit that Zhang et al. 2 use the nomenclature H3Se for the molecular (H2Se)2H2 at low pressure , we stress that this was made on purpose to emphasize the connection to the expected high-pressure behavior that is analogous with the behavior of H3S . Furthermore, Pace et al. 1 suggests that the structural description of the compound is incorrect proposing that I4/mcm space group is a better choice. However, they admit themselves that XRD of these structures are very similar as the predicted peak positions and intensities are mainly determined by the positions of heavy Se, and these positions are almost indistinguishable in these two structures. The XRD data presented by Zhang et al. 2 have been collected using very small samples (a few single crystals, each of which was a few micrometers in linear dimensions) that were synthesized by laser heating in a diamond anvil cell (DAC) at nearly 5 GPa. Unfortunately, a complete structural analysis was not possible in our DAC with a limited angular opening. In this case, it is plausible to use theoretical predictions as a guide, and the results of Zhang et al. 2 showed a quite good correspondence with the predicted Cccm structure . XRD of this low symmetry structure has many peaks of very low intensities and many peaks coincide; to facilitate
