The Triple Point of Xenon as a Possible Defining Point on an International Temperature Scale

Kemp, R C; Kemp, W R G; Smart, P W

doi:10.1088/0026-1394/21/2/001

Cited by 13 publications

(6 citation statements)

References 8 publications

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“…18 Our adsorption isotherm measurements span seven temperatures in the range between 95 and 160 K. All of the temperatures in this interval are below xenon's triple point (T t = 161.389 K), so solid xenon is the phase that condenses at saturation in our measurements. 28 In all cases, the measurements were started from a freshly re-evacuated sample (i.e., from zero loading) and were continued, without re-evacuation, until the equilibrium pressure reached saturation.…”

Section: Resultsmentioning

confidence: 99%

Evidence of Gate-Opening on Xenon Adsorption on ZIF-8: An Adsorption and Computer Simulation Study

2016

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We report on experimental (thermodynamics and kinetics) and computer simulation results for Xe sorption in ZIF-8. At temperatures below ∼145 K, there are two substeps present in adsorption isotherms (before saturation is reached). The substep that occurs at higher loadings was identified as corresponding to ZIF-8’s gate-opening transition. Above 145 K, this higher-loading substep is no longer resolvable. We determined the isosteric heat of adsorption for this system and obtained a value of 244 meV for sorption on the more strongly binding sites in the ZIF-8. We found that there is a peak in the isosteric heat of adsorption, as a function of sorbent loading, associated with the gate-opening transition. We estimated the heat of transition for gate-opening to have an upper bound of ∼30 meV. Our results for the isotherms and the isosteric heats are compared with those from our Monte Carlo computer simulations, obtained using both the structure of ZIF-8 before and after the gate-opening transition and a new set of mixed Lennard-Jones parameters. We conducted measurements for the sorption kinetics for this system. We found that, while the sorption occurs faster as the loading increases before the gate-opening transition, the equilibration times increase with loading in the gate-opening region, resulting in an unusual nonmonotonic behavior for the variation of this quantity as a function of sorbent loading.

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Section: Resultsmentioning

confidence: 99%

Evidence of Gate-Opening on Xenon Adsorption on ZIF-8: An Adsorption and Computer Simulation Study

2016

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“…K ) with its triple point does not appreciably change the non-uniqueness. point is not sufficiently reproducible to be used for this purpose because of difficulties in obtaining gas of high purity and reproducible isotopic composition [17]. Consequently, the mercury triple point (234.3 156 K) was chosen as the best compromise, being more reproducible than the triple point of xenon, but less suitably located.…”

Section: Temperatures Fvom 138 K To 27316 Kmentioning

confidence: 99%

The Platinum Resistance Thermometer Range of the International Temperature Scale of 1990

et al. 1991

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Within the International Temperature Scale of 1990 (ITS-90) the platinum resistance thermometer (PRT) is used to realize the scale from approximately 13,8 K to 1 235 K. Such a temperature range is wider than the corresponding range in the International Practical Temperature Scale of 1968 (IPTS-68) because the PRT is used up to the freezing point of silver (1 234,93 K). In this way, the ITS-90 can be realized with much more precision than the IPTS-68, particularly between 901 K and 1 235 K where the standard Pt-10% Rh vs Pt thermocouple was previously used.This paper describes some important steps in the construction of the PRT reference function and the criteria for the selection of the PRT interpolating equations of the ITS-90. In contrast to previous international scales, the PRT range of the ITS-90 is based on two reference functions, one from 13,8 K to 273,16 K and the other from 273,15 K to 1 234,93 K. The two reference functions were obtained from two real PRTs.A set of interpolating equations is used to account for the differences of other real PRTs from those on which the reference functions are based. They provide flexibility of calibration and high precision as expressed, for instance, by non-uniqueness and sub-range inconsistency not exceeding 0,5 mK over the range from 13,8 K to 693 K. Such good properties are the consequence of the choice of suitable forms for the interpolating equations and of fine adjustments in the values assigned to some defining fixed points.

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“…The triple point of xenon has long been recognized [1] as a potentially useful calibration point for the International Temperature Scale (ITS). As work progressed towards the revision of the ITS during the late 1980s, the triple point of xenon was proposed [2][3][4] as a defining fixed point of the ITS-90 [5] due to its desirable placement (160.405 K [6]) nearly halfway between the triple point of argon (83.8058 K) and the triple point of water (TPW) (273. 16 K).…”

Section: Introductionmentioning

confidence: 99%

“…Reports of the thermal behaviour of xenon invariably indicated that the broad melting range and the extent of the variation in liquidus points (liquid fraction equal to 1) among different samples precluded its adoption as a defining point [2,[7][8][9][10][11][12][13][14]. There was speculation but no conclusion as to whether this variability was due to impurity content or isotopic composition.…”

Section: Introductionmentioning

confidence: 99%

The triple point of xenon

Hill

Steele

2005

Metrologia

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The triple point of xenon is shown to be a suitable fixed point for incorporation into the next revision of the International Temperature Scale (ITS) as a means of reducing the non-uniqueness in the important 84 K to 273 K range. Isotopic effects, once thought to be a limiting factor, are shown to be negligible. Purity remains the overriding concern, but high-purity xenon gas is obtainable, giving a very flat plateau with a melting range within ±10 µK from 50% to 90% of the melted sample fraction. The triple point temperature of xenon is shown to be 161.405 96 K ± 0.32 mK (k = 1) on the ITS-90. The propagated calibration uncertainty of the platinum resistance thermometers and the component attributed to the non-uniqueness of the ITS-90, as evidenced by the differences among the seven calibrated thermometers, dominate the overall uncertainty of the estimated triple point temperature. The xenon triple point itself is highly reproducible, with a standard deviation of 48 µK for the eight melts of this study and a total realization uncertainty of just 76 µK.

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The Triple Point of Xenon as a Possible Defining Point on an International Temperature Scale

Cited by 13 publications

References 8 publications

Evidence of Gate-Opening on Xenon Adsorption on ZIF-8: An Adsorption and Computer Simulation Study

Evidence of Gate-Opening on Xenon Adsorption on ZIF-8: An Adsorption and Computer Simulation Study

The Platinum Resistance Thermometer Range of the International Temperature Scale of 1990

The triple point of xenon

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