High-pressure Raman study of dense methane: CH4 and CD4

✍ Scribed by Y. H. Wu; S. Sasaki; H. Shimizu

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 389 KB
• Volume: 26
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.1250261007

✦ Synopsis

Abstract

High‐pressure Raman spectra of liquid and solid CH~4~ and CD~4~ were measured up to 18 and 13 GPa, respectively, at 300 K in a gasketed diamond‐anvil cell. On the basis of visual observations under the polarizing microscope and changes in the Raman spectra, it was confirmed that there are only two solid phases (I and VII) for CH~4~ and CD~4~ at 300 K up to 18 GPa; no solid‐solid phase transition was found around 12 GPa, in contrast to earlier claims. In phase VII, some molecules are orientationally ordered, whereas others are orientationally disordered, just like the low‐temperature solid phases II, III, IV and V.