SUPPLEMENTARY MATERIAL Hereafter we furnish some details about the operation we deemed as necessary to address in an appropriate thermodynamic context the various experiments Shelby (1976) The experiment refer actually to dissolved noble gases (He, Ne) in silica glass, so it is only of partial interest here. Shelby1 choose to represent the data in terms of number of dissolved atoms per cm3 of glass. To do this he multiplied the volume V of the total system (container + gauge + valves + tubing) expressed in cm3 by the final system pressure P in atm, by the density of He (or Ne) at room conditions, by the density of vitreous silica, dividing by the weight of specimen in g: C 5.42 1019 atoms g cm 3 atm g , cm 3 cm 3 (1) The constant 5.42×1019 is equal to the density of He (at 25 °C and 1 atm) in atoms/cm3 multiplied by the density in g/ cm3 of vitreous silica. Dividing C by Avogadro number N° one obtains the number of moles of He in the glass. : 5.42 1019 mol C' 9.00 10 5 atm (2) 23 6.02 10 cm 3 The molar volume of silica glass is 27.276 cm3/mol, hence the molar fraction of gas in the liquid is 2.456×10-3 and we get LnKH,He = 6.009. Shelby1 refitted his data in form of a Langhmuir isotherm C K f V0 1 K f (3) where f is fugacity (assumed to be equal to pressure at sufficiently low pressure), K is a (Pdependent) constant and V0 is the number of atoms per cm3 of glass. The obtained values are 1.95×10-4 for He and 2.51×10-4 for Ne. Assuming these values to be true solubility constants we would get, in terms of Henry's Law LnKH,He = 8.54 and LnKH,Ne=8.29. Probably the constants are only operative and return the concentration in atoms. Finally, the fact that E in eq. 8 of Shelby1 is a "binding energy" and the assumption of a vibrational contribution of the trapped gas is hard to share. Most likely E may be assumed to correspond to the electrostatic+repulsive+dispersive interaction of the atom with the reaction field and the gas is monatomic and unbounded, so that no vibrational contributions are present. The values of E (-1.05 kcal/mol for He and -2.00 kcal/mol for Ne) are roughly consistent with our PCM estimates. Kirsten (1968) The experiment on molten enstatite (0.5MgO-0.5SiO2) is described very carefully2. The results obtained stemming from the observed concentration/partial pressure slope are expressed in terms of a dimensional solubility as follows: cm 3STP K He 1.2 10 4 atm g (4.1) 1 cm 3STP K Ne 0.7 10 4 atm g (4.2) cm 3STP K He 0.2 10 4 atm g (4.3) It should be noted that the term STP (Standard Temperature and Pressure) has not an unique significance. According to IUPAC recommendations3 in chemical thermodynamics the volume of reduced gas must refer to 298.15 K, 10-5 Pa, while the recommended T and P in the Glossary of Atmospheric Terms4 are 273.15 K and 10-5 Pa. In common practice however one uses sometimes 298.15 K and 1 atm (1.01325 × 10-5 Pa) and must often 273.15 K, 1 atm. The conversion constants to obtain the reduced gas volume are respectively in the four cases 24789.560, 22710.953, 24465.402 and 22413.968. We will assume hereafter that all Authors adopted the last conversion (usually rounded off to 22414) in retrieving their experimental results. The molar fraction of trace component in the liquid (Xi,l) is then obtained by multiplying the number of moles per gram of substance ni/g by the molar weight of the solvent (MW) : X i ,l n i g MW (5) The units adopted by Kirstens2 are [(cm3 STP/g)×atm]. Assuming enstatite to be pure we have for the liquid a molar weight pm=50.205 g, hence LnKH,He=15.130, LnKH,Ne=15.669, LnKH,Ar=16.921. In the experiment of Kirstens the quenching procedure consisted simply in turning off the heating current, so the nominal T of equilibration (1500°C) must be considered as a high T limit. Shibata et al. (1998) The experiments are well detailed and pose no interpretative problems5. Possible He loss from samples before analyses was inferred by the authors from the large variation in He data and the high He blank during the analysis. The high quenching rate (200°C/sec) ensure that the measured noble element concentration in the glass corresponds to the equilibrium value in the former liquid. However, we have seen in Shelby1 that in solid glass the departure from Henry's Law behavior are quite immediate (see particularly figures 3 and 5 in Shelby1). The pressure range investigated by Kirsten2 on the other hand is too limited for practical appraisals concerning silicate liquids (maximum partial pressure = 420 Torr 0.56 bar). The data of Shibata et al.5 are in dimensional form [(cm3 STP/g)×bar] and already scaled to 1 bar based on the calculated fugacity of the gaseous component (see their tables 2 and 5) which is the correct procedure3. In Table A1 we report the magnitudes adopted for calculations after conversion of the dimensional solubility into Henry's Law constants. Table A1: Liquid Samples in the Shibata et al.5 experiment. _______________________________________________________________________________________________________________________ 2 Magnitude NCS1 Molar volume (cc/mol) 24.965 22.517 21.213 24.315 24.651 25.094 19.247 19.009 18.781 18.419 Molar weight (g/mol) 60.929 59.882 59.231 60.736 60.647 60.512 56.548 54.779 52.959 50.905 Density (g/cc) 2.441 2.659 2.792 2.498 2.460 2.411 2.938 2.882 2.820 2.764 Molecular volume (Å3) 41.456 37.390 35.226 40.375 40.934 41.670 31.960 31.565 31.187 30.586 (Å-3) 0.02412 0.02675 0.02839 0.02477 0.02443 0.02400 0.03129 0.03168 0.03206 0.03269 rcoll (Å) 1.489 1.438 1.410 1.476 1.482 1.491 1.365 1.359 1.354 1.345 Static polarizability (Å3) 5.610 5.457 5.283 5.807 5.668 5.481 4.818 4.602 4.380 4.135 Numeral density NCS2 NCS3 NS1 NS2 NS3 CMS1 CMS2 CMS3 MS1 4.927 5.718 6.068 5.546 5.144 4.682 6.139 5.707 5.287 4.918 ×105 K-1 7.405 8.894 9.028 9.792 8.306 6.371 8.293 7.604 6.876 6.233 '×109 -4.857 -6.851 -6.939 -8.197 -6.028 -3.653 -5.885 -5.007 -4.147 -3.428 K-2 β×106 bar-1 7.033 5.670 4.743 7.261 7.128 6.942 3.239 3.000 2.766 2.462 _______________________________________________________________________________________________________________________ Hiyagon and Ozima (1986) The experiment was meant to investigate trace partitioning between melt and phenocrysts growing frm the melt6. Hence the true composition of the liquid at equilibrium with the gas atmosphere could differ appreciably from the nominal composition of the starting materials, which are two mixtures of basalt and harzburgite (Table 1 in Hiyagon and Ozima6). Minor contamination effects with the alumina crucible were also observed by the authors. Likely He loss from the liquid samples is also declared by the authors. We investigated particularly the BH series results with experiments carried out at 105 Pa. The assumed equilibrium temperature is 1300°C for the whole series. Results in the original paper are listed as dimensional magnitudes with different scaling factors, i.e. cm 3STP cm 3STP 8 10 for He, Ne, Ar and 1010 for Kr and Xe. For all the above recalled g g problems we consider the data as simply qualitative at best. Table A2: Starting compositions in the Hiyagon and Ozima experiment6. 3 __________________________________________________ Magnitude Mixture A Mixture B Molar volume (cc/mol) 20.508 19.796 Molar weight (g/mol) 60.598 58.894 Density (g/cc) 2.955 2.975 Molecular volume (Å3) 34.055 32.871 Numeral density (Å-3) 0.02936 0.03042 rcoll (Å) 1.394 1.378 Static polarizability (Å3) 4.782 4.683 5.285 5.439 ×105 K-1 8.262 8.523 '×109 -5.926 -6.281 K-2 β×106 bar-1 3.791 3.462 __________________________________________________ Jambon et al. (1986) The starting material in the experiment of Jambon et al.7 is a natural tholeiitic basalt. Experiments were performed between 1200°C and 1600°C. No details on the quenching rate are given but a very accurate investigation of reproducibility, dependence on grain size and time equilibration ensures a high quality of results. There is moreover a reversal experiment carried out at 1500 °C. Results are listed in units of cm 3STP 10 5 g bar 4 Table A3: Starting compositions in the experiments of Kirstens2 and Jambon et al.7 _____________________________________________________________ Magnitude Kirstens (1968) Janbon et al. (1986) Molar volume (cc/mol) 17.947 21.280 Molar weight (g/mol) 50.190 62.494 Density (g/cc) 2.797 2.937 (Å3) 29.802 35.336 Numeral density (Å-3) 0.03355 0.02830 1.334 1.411 4.080 4.984 5.032 5.331 ×105 K-1 6.554 8.410 '×109 K-2 -3.788 -6.040 Molecular volume rcoll (Å) Static polarizability (Å3) β×106 bar-1 2.258 4.353 _____________________________________________________________ Lux (1987) The starting materials were crushed powders of natural lava8. To prevent loss of iron from the material into the crucible a high oxygen partial pressure was maintained during equilibration. The nominal amount of Fe2O3 thus increased during equilibration at the expenses of FeO (see Table 1 in Lux, 1987). Quenching was obtained by electrically fusing a wire link and releasing the sample charge into a cool zone (25-30°C). Results are given in terms of cm 3STP / g / a 10 5 here cm 3STP 10 5 . reinterpreted as g bar 5 Hereafter we furnish some detail relative to the SPT-PCM computation for Ar in the various media. Table A4: SPT-PCM calculations for Ar in the media investigated by Kirsten2 and Jambon et al.7 _________________________________________________________________ Magnitude Kirsten (1976) Jambon et al. (1986) mean T=1500 °C Jambon et al. (1986) reversal T=1500 °C Gcav kJ/mol 24.175 21.102 20.964 Hcav kJ/mol 1.002 1.084 1.073 Scav J/(mol×K) -77.7 -67.1 -66.7 Hint kJ/mol -15.523 -13.096 -13.096 G°solution kJ/mol 26.577 25.507 25.370 H°solution kJ/mol -16.952 -14.430 -14.441 S°solution J/(mol×K) -145.997 -133.951 -133.524 -1.107 -0.429 -0.523 -5.207 -5.907 -5.816 LnKH,298.15 10.721 10.289 10.234 LnKH P,T exper. 16.920 15.616 15.568 H°f,solute kJ/mol -26.539 -24.085 -24.096 S°solute J/(mol×K) -0.8 11.4 11.8 V°solute J/bar 1.909 1.965 1.963 a CP solute J/(mol×K) 19.683 20.361 20.267 -5.207 -5.907 -5.816 1.390 1.458 1.456 a CP solution J/(mol×K) J/(mol×K2) b CP solution b CP solute J/(mol×K2) rsolv at target KH (Å) ____________________________________________________________ 6 Table A5: SPT-PCM calculations for Ar in the media investigated by Shibata et al.5 ______________________________________________________________________________________________________________ Magnitude NCS1-G205 NCS1-G206 NCS1-G209 NCS1-G211 NCS2-G205 NCS2-G206 NCS2-G209 NCS2-G211 NCS3-G211 Gcav kJ/mol 19.366 20.871 18.344 17.787 22.853 23.901 22.040 21.138 23.434 Hcav kJ/mol 0.876 0.981 0.811 0.777 1.309 1.402 1.244 1.172 1.360 Scav J/(mol×K) -62.0 -66.7 -58.8 -57.1 -72.3 -75.5 -69.8 -67.0 -74.0 Hint kJ/mol -11.171 -11.171 -11.171 -11.171 -12.385 -12.385 -12.385 -12.385 -13.138 G°solution kJ/mol 25.301 26.806 24.279 23.722 27.830 28.878 27.017 26.115 27.806 H°solution kJ/mol -12.721 -12.616 -12.786 -12.819 -13.490 -13.398 -13.555 -13.626 -14.192 S°solution J/(mol×K) -127.5 -132.2 -124.3 -122.6 -138.6 -141.8 -136.1 -133.3 -140.9 a CP solution J/(mol×K) -1.835 -0.908 -2.459 -2.791 1.743 2.583 1.092 0.399 1.983 -4.790 -5.676 -4.100 -3.709 -8.444 -9.321 -7.635 -6.825 -8.447 LnKH,298.15 10.206 10.813 9.794 9.569 11.226 11.649 10.898 10.534 11.216 LnKH P,T exper. 14.745 15.279 14.481 14.374 15.875 16.236 15.692 15.472 16.280 H°f,solute kJ/mol -19.862 -19.589 -20.812 -21.684 -20.229 -20.062 -21.271 -22.327 -22.914 S°solute J/(mol×K) 18.8 14.5 21.2 22.4 9.1 6.2 10.8 12.9 5.8 V°solute J/bar 2.039 2.072 2.017 2.005 2.047 2.067 2.032 2.016 2.013 a CP solute J/(mol×K) 18.955 19.882 18.331 17.999 22.533 23.373 21.882 21.189 22.773 -4.790 -5.676 -4.100 -3.709 -8.444 -9.321 -7.635 -6.825 -8.447 1.538 1.563 1.519 1.508 1.521 1.534 1.509 1.496 1.489 J/(mol×K2) b CP solution b CP solute J/(mol×K2) rsolv at target KH (Å) 7 Magnitude NCS3-G211 Gcav kJ/mol 23.434 Hcav kJ/mol Scav J/(mol×K) NS1-G206 NS1-G209 NS1-G211 NS2-G205 NS2-G206 NS2-G209 NS2-G211 21.590 21.503 21.310 20.607 20.625 23.068 19.360 19.183 1.360 1.343 1.335 1.323 1.263 1.073 1.272 0.979 0.969 -74.0 -67.9 -67.6 -67.0 -64.9 -65.6 -73.1 -61.6 -61.1 Hint kJ/mol -13.138 -11.464 -11.464 -11.464 -11.464 -11.339 -11.339 -11.339 -11.339 G°solution kJ/mol 27.806 27.297 27.210 27.016 26.314 26.424 28.866 25.158 24.982 H°solution kJ/mol -14.192 -12.529 -12.538 -12.550 -12.609 -12.685 -12.486 -12.779 -12.788 S°solution J/(mol×K) -140.9 -133.6 -133.3 -132.7 -130.5 -131.2 -138.7 -127.2 -126.7 a CP solution J/(mol×K) 1.983 2.054 1.979 1.802 1.207 -0.202 1.590 -1.094 -1.224 -8.447 -8.821 -8.741 -8.414 -7.680 -6.410 -8.227 -5.412 -5.189 LnKH,298.15 11.216 11.011 10.976 10.898 10.615 10.659 11.644 10.148 10.077 LnKH P,T exper. 16.280 15.342 15.312 15.339 15.185 15.121 15.972 14.775 14.802 H°f,solute kJ/mol -22.914 -19.295 -19.309 -20.290 -21.358 -19.594 -19.179 -20.630 -21.503 S°solute J/(mol×K) 5.8 14.2 14.4 14.4 15.8 15.8 9.0 18.9 18.9 V°solute J/bar 2.013 2.093 2.091 2.086 2.070 2.068 2.126 2.039 2.036 a CP solute J/(mol×K) 22.773 22.844 22.769 22.592 21.997 20.588 22.380 19.696 19.566 -8.447 -8.821 -8.741 -8.414 -7.680 -6.410 -8.227 -5.412 -5.189 1.489 1.555 1.554 1.551 1.540 1.550 1.586 1.529 1.526 NS3-G209 NS3-G211 CMS1-G212 CMS1-G215 CMS2-G212 18.150 17.597 18.833 18.083 18.291 J/(mol×K2) b CP solution b CP solute J/(mol×K2) rsolv at target KH (Å) NS1-G205 Magnitude NS3-G205 NS3-G206 Gcav kJ/mol 19.161 20.641 CMS3-G212 18.179 MS1-G156 23.883 8 Hcav kJ/mol 0.747 0.835 0.691 0.662 0.880 0.832 0.773 0.694 0.944 Scav J/(mol×K) -61.8 -66.4 -58.6 -56.8 -60.2 -57.9 -58.8 -58.6 -76.9 Hint kJ/mol -11.088 -11.088 -11.088 -11.088 -14.435 -14.435 -14.644 -14.853 -15.146 G°solution kJ/mol 25.167 26.647 24.156 23.603 22.149 21.399 21.429 21.138 26.597 H°solution kJ/mol -12.773 -12.685 -12.829 -12.858 -15.973 -16.021 -16.294 -16.587 -16.636 S°solution J/(mol×K) -127.3 -131.9 -124.0 -122.3 -127.9 -125.5 -126.5 -126.5 -145.006 a CP solution J/(mol×K) -2.851 -2.076 -3.380 -3.664 -2.323 -2.775 -3.167 -3.758 -1.569 -3.835 -4.539 -3.265 -2.938 -4.170 -3.698 -3.410 -2.899 -4.693 LnKH,298.15 10.152 10.749 9.744 9.521 8.934 8.632 8.644 8.527 10.729 LnKH P,T exper. 14.752 15.286 14.488 14.381 14.868 14.693 14.726 14.737 16.933 H°f,solute kJ/mol -20.113 -19.848 -21.033 -21.878 -25.771 -26.714 -26.177 -26.560 -27.131 S°solute J/(mol×K) 18.5 14.3 21.0 22.2 16.7 18.4 17.6 17.3 -0.4 V°solute J/bar 2.032 2.065 2.011 2.000 1.900 1.893 1.889 1.882 1.917 a CP solute J/(mol×K) 17.939 18.714 17.410 17.126 18.462 18.015 17.622 17.031 19.221 -3.835 -4.539 -3.265 -2.938 -4.167 -3.697 -3.411 -2.899 -4.693 1.538 1.563 1.519 1.508 1.356 1.342 1.338 1.328 1.403 J/(mol×K2) b CP solution b CP solute J/(mol×K2) rsolv at target KH (Å) _____________________________________________________________________________________________________________________________________ 9 Table A6: SPT-PCM calculations for Ar in the media investigated by Hiyagon and Ozima6 ____________________________________________________________________________________ Magnitude BH-257 BH-258 BH-266 BH-267 BH-271 BH-275 BH-276 Gcav kJ/mol 27.579 26.299 26.845 27.338 29.609 26.798 26.245 Hcav kJ/mol 1.587 1.475 1.555 1.599 1.808 1.550 1.502 Scav J/(mol×K) -87.2 -83.3 -84.8 -86.3 -93.2 -84.7 -83.0 Hint kJ/mol -13.598 -13.598 -14.100 -14.100 -14.100 -14.100 -14.100 G°solution kJ/mol 31.575 30.294 30.426 30.919 33.190 30.378 29.826 H°solution kJ/mol -14.430 -14.542 -14.963 -14.919 -14.709 -14.967 -15.016 S°solution J/(mol×K) -154.300 -150.381 -152.234 -153.740 -160.655 -152.089 -150.401 4.143 3.128 3.758 4.159 6.071 3.720 3.278 -10.735 -9.677 -10.371 -10.791 -12.832 -10.331 -9.870 LnKH,298.15 12.737 12.220 12.273 12.472 13.388 12.254 12.031 LnKH P,T exper. 17.697 17.255 17.424 17.594 18.372 17.408 17.218 H°f,solute kJ/mol -21.955 -22.098 -22.543 -22.490 -22.276 -22.548 -22.611 S°solute J/(mol×K) -6.3 -2.7 -4.4 -5.7 -12.1 -4.2 -2.7 V°solute J/bar 2.026 2.009 1.996 2.002 2.031 1.995 1.988 a CP solute J/(mol×K) 24.933 23.918 24.548 24.949 26.861 24.510 24.068 -10.735 -9.677 -10.371 -10.791 -12.832 -10.331 -9.870 1.514 1.500 1.483 1.488 1.510 1.483 1.477 a CP solution J/(mol×K) J/(mol×K2) b CP solution b CP solute J/(mol×K2) rsolv at target KH (Å) _____________________________________________________________________________________ References 1 Shelby J.E. (1976) J. Appl. Phys.,47, 136-139 2 Kirsten T. (1968) J. Geophys. Res., 73, 2807-2810 3 Schwartz S.E. and Warneck P. (1995) Pure Appl. Chem.,67, 1377-1406 4 Calvert J.G. (1990) Pure Appl. Chem. 62, 2267-2219 6 Hiyagon H. and Ozima M. (1986) Geochim. Cosmochim. Acta, 50, 2045-2057 7 Janbon A., Weber H. and Braun O. (1986) Geochim. Cosmochim. Acta, 50, 401-408 8 Lux G. (1987) Geochim. Cosmochim. Acta, 51, 1549-1560 10