Ruby under pressure

Abstract

The ruby luminescence method is widely used for pressure measurement in the diamond anvil cell and other optically transparent pressure cells. With this application in mind, we briefly review the ground-state physical properties of corundum (α-Al₂O₃) with some emphasis on its behavior under high pressure, survey the effects of temperature and stress on the R-line luminescence of ruby (Cr-doped corundum), and address the recent efforts towards an improved calibration of the R-line shift under hydrostatic pressures beyond the 50 GPa mark.

Keywords:

• corundum
• ruby
• luminescence
• high pressure
• ruby pressure scale

Acknowledgements

The author has enjoyed discussions with W.B. Holzapfel, M.F. Nicol, and I. Loa. Thanks goes to P. Loubeyre, A.R. Oganov, and D. Klug for exchange of information. Stefan Klotz, the Editor in Chief of this journal, asked to reshape circulating notes into a contribution for HPR; the pressure he exercised concerning the finishing of the manuscript has been very gentle.

Notes

^†The Vinet form is now also called Rydberg–Vinet relation; the analytical form was derived from a Rydberg interatomic potential 52 by Stacey et al. 53, with typos being pointed out in 54. The limit of Rydberg–Vinet corresponds to a Biot finite-strain EOS (Lagrangian frame) or, equivalently, to the EOS of a monatomic ‘harmonic solid’ where nearest neighbors interact via a harmonic central force.

Additional information

Notes on contributors

K. Syassen

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