Raman studies to 104 GPa of a 14N2 host with dilute 15N2 and 14N15N isotopic species indicate an increase in vibrational coupling with pressure. The lowest frequency branch of the isotopic species 15N2 reaches a plateau around 100 GPa suggesting the onset of bond weakening for molecules located on particular sites. An unusual intensity increase is observed for the isotopic ν1 guest modes. The phase transitions above 20 GPa appear to involve an increase in the number of inequivalent sites, with possibly subtle changes in the orientational behavior of particular molecules in the pressure range 25 to 50 GPa not readily revealed in recent x-ray diffraction studies.
ASJC Scopus subject areas
- Physics and Astronomy(all)