Ruby pressure scale

File:Ruby fluorescence spectra at 1atm, 2.23 GPa and 4 GPa.png The ruby fluorescence pressure scale is an optical method to measure pressure within a sample chamber of a diamond anvil cell apparatus.{{Cite journal|last=Bassett|first=William A.|date=2009-05-21|title=Diamond anvil cell, 50th birthday|url=http://dx.doi.org/10.1080/08957950802597239|journal=High Pressure Research|volume=29|issue=2|pages=163–186|doi=10.1080/08957950802597239|s2cid=15204168 |issn=0895-7959|url-access=subscription}} Since it is an optical method, which fully make use of the transparency of diamond anvils and only requires an access to a small scale laser generator, it has become the most prevalent pressure gauge method in high pressure sciences.

Principles

Ruby is chromium-doped corundum (Al₂O₃). The Cr³⁺ in corundum's lattice forms an octahedra with surrounding oxygen ions. The octahedral crystal field together with spin-orbital interaction results in different energy levels. Once 3d electrons in Cr³⁺ are energized by lasers, the excited electrons would go to ⁴T₂ and ²T₂ levels. Later they return to ²E levels and the R₁, R₂ lines come from luminescence from ²E levels to ⁴A₂ ground level.{{Cite journal|last=Syassen|first=K.|date=June 2008|title=Ruby under pressure|url=http://www.tandfonline.com/doi/abs/10.1080/08957950802235640|journal=High Pressure Research|language=en|volume=28|issue=2|pages=75–126|doi=10.1080/08957950802235640|s2cid=95275637 |issn=0895-7959|url-access=subscription}} The energy difference of ²E levels are 29 cm⁻¹, corresponding to the splitting of R₁, R₂ lines at 1.39 nm.

Development

Ruby fluorescence spectra has two strong sharp lines, R₁ and R_2. R₁ refers to the stronger intensity and lower energy (longer wavelength) excitation and is used to gauge pressure.

Pressure is calculated as: $P(Mbar)=\frac{a}{b}[\left ( \frac{\lambda}{\lambda_0} \right )^b-1]$ , where λ₀ is the R₁ wavelength measured at 1atm, a and b are constants. (e.g. a = 19.04, b = 5{{Cite journal|last1=Mao|first1=H. K.|last2=Bell|first2=P. M.|last3=Shaner|first3=J. W.|last4=Steinberg|first4=D. J.|date=June 1978|title=Specific volume measurements of Cu, Mo, Pd, and Ag and calibration of the ruby "R₁" fluorescence pressure gauge from 0.06 to 1 Mbar|url=http://aip.scitation.org/doi/10.1063/1.325277|journal=Journal of Applied Physics|language=en|volume=49|issue=6|pages=3276–3283|doi=10.1063/1.325277|issn=0021-8979|url-access=subscription}})

Since first demonstrated by Forman and colleagues in 1972,{{Cite journal|last1=Forman|first1=Richard A.|last2=Piermarini|first2=Gasper J.|last3=Barnett|first3=J. Dean|last4=Block|first4=Stanley|date=1972-04-21|title=Pressure Measurement Made by the Utilization of Ruby Sharp-Line Luminescence|url=http://dx.doi.org/10.1126/science.176.4032.284|journal=Science|volume=176|issue=4032|pages=284–285|doi=10.1126/science.176.4032.284|pmid=17791916 |s2cid=8845394 |issn=0036-8075|url-access=subscription}}{{Cite journal|last=Piermarini|first=G.J.|date=Nov 2011|title=High pressure X-ray crystallography with the diamond cell at NIST/NBS|journal=Journal of Research of the National Institute of Standards and Technology|volume=106|issue=6|pages=910–912|doi=10.6028/jres.106.045|pmid=27500054 |pmc=4865304 |s2cid=18150811 |issn=1044-677X|doi-access=free}} many scientists have contributed to the establishment of accurate ruby pressure scale in various experimental conditions.

A likely incomplete summary of is given below:

class="wikitable"

!Year

!First Author

!Primary pressure standard used

!Temperature

!Pressure range

!Pressure transmitting medium

!References

1972

|R. A. Forman

| -

|-, linear

|Transitions of CCl₄, H₂O, C₂H₅Br, n-C₇H₁₆

|Room temperature

|2.2 GPa

|See standards used

1978

|H. K. Mao

|1904

|Ag, Cu, Mo, Pd

|Room temperature

|6 - 100 GPa

|M-E, H₂O

1986

|H. K. Mao

|1904

|7.665

|Cu, Ag, Ar

|Room temperature

|80 GPa

|Ar

|{{Cite journal|last1=Mao|first1=H. K.|last2=Xu|first2=J.|last3=Bell|first3=P. M.|date=1986|title=Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions|url=http://dx.doi.org/10.1029/jb091ib05p04673|journal=Journal of Geophysical Research|volume=91|issue=B5|pages=4673|doi=10.1029/jb091ib05p04673|issn=0148-0227|url-access=subscription}}

2004

|A. Dewaele

|1904

|9.5

|Al, Cu, W

|Room temperature

|153 GPa

|Helium

|{{Cite journal|last1=Dewaele|first1=Agnès|last2=Loubeyre|first2=Paul|last3=Mezouar|first3=Mohamed|date=2004-09-22|title=Equations of state of six metals above94GPa|url=http://dx.doi.org/10.1103/physrevb.70.094112|journal=Physical Review B|volume=70|issue=9|doi=10.1103/physrevb.70.094112|issn=1098-0121|url-access=subscription}}

2005

|A. D. Chijioke

|1876(6.7)

|10.71(0.14)

|Au, Pt

|Room temperature

|150 GPa

|Helium, Hydrogen, Ar

|{{Cite journal|last1=Chijioke|first1=Akobuije D.|last2=Nellis|first2=W. J.|last3=Soldatov|first3=A.|last4=Silvera|first4=Isaac F.|date=Dec 2005|title=The ruby pressure standard to 150GPa|url=http://aip.scitation.org/doi/10.1063/1.2135877|journal=Journal of Applied Physics|language=en|volume=98|issue=11|pages=114905|doi=10.1063/1.2135877|issn=0021-8979}}

2008

|S.D Jacobsen

|1904

|10.32(7)

|MgO

|Room temperature

|118 GPa

|Helium

|{{Cite journal|last1=Jacobsen|first1=S. D.|last2=Holl|first2=C. M.|last3=Adams|first3=K. A.|last4=Fischer|first4=R. A.|last5=Martin|first5=E. S.|last6=Bina|first6=C. R.|last7=Lin|first7=J.-F.|last8=Prakapenka|first8=V. B.|last9=Kubo|first9=A.|last10=Dera|first10=P.|date=2008-11-01|title=Compression of single-crystal magnesium oxide to 118 GPa and a ruby pressure gauge for helium pressure media|url=http://dx.doi.org/10.2138/am.2008.2988|journal=American Mineralogist|volume=93|issue=11–12|pages=1823–1828|doi=10.2138/am.2008.2988|s2cid=21661728 |issn=0003-004X|url-access=subscription}}

2012

|H. Yamaoka

|1762*ln(λ/λ₀)

|Ruby R₁

|Low temperature to 16K

|26 GPa

|M-E, Silicone oil

|{{Cite journal|last1=Yamaoka|first1=Hitoshi|last2=Zekko|first2=Yumiko|last3=Jarrige|first3=Ignace|last4=Lin|first4=Jung-Fu|last5=Hiraoka|first5=Nozomu|last6=Ishii|first6=Hirofumi|last7=Tsuei|first7=Ku-Ding|last8=Mizuki|first8=Jun'ichiro|date=2012-12-15|title=Ruby pressure scale in a low-temperature diamond anvil cell|url=http://aip.scitation.org/doi/10.1063/1.4769305|journal=Journal of Applied Physics|language=en|volume=112|issue=12|pages=124503|doi=10.1063/1.4769305|issn=0021-8979|url-access=subscription|doi-access=free}}

2020

|G. Shen

|1870

|5.63(3)

|MgO, Mo, Cu, Diamond

|Room temperature

|150 GPa

|Helium

|{{Cite journal|last1=Shen|first1=Guoyin|last2=Wang|first2=Yanbin|last3=Dewaele|first3=Agnes|last4=Wu|first4=Christine|last5=Fratanduono|first5=Dayne E.|last6=Eggert|first6=Jon|last7=Klotz|first7=Stefan|last8=Dziubek|first8=Kamil F.|last9=Loubeyre|first9=Paul|last10=Fat’yanov|first10=Oleg V.|last11=Asimow|first11=Paul D.|date=2020-07-02|title=Toward an international practical pressure scale: A proposal for an IPPS ruby gauge (IPPS-Ruby2020)|url=https://www.tandfonline.com/doi/full/10.1080/08957959.2020.1791107|journal=High Pressure Research|language=en|volume=40|issue=3|pages=299–314|doi=10.1080/08957959.2020.1791107|s2cid=225460396 |issn=0895-7959}}

References

Category:High pressure science

Category:Optics

Category:Applied and interdisciplinary physics