Sulfur dioxide !Short name 7446-09-5 !CAS number Sulfur dioxide !Full name SO2 !Chemical formula {O2S} R-764 !Synonym 64.0638 !Molar mass [g/mol] 197.7 !Triple point temperature [K] 263.137 !Normal boiling point [K] 430.64 !Critical temperature [K] 7886.6 !Critical pressure [kPa] 8.078 !Critical density [mol/L] 0.256 !Acentric factor 1.6 !Dipole moment [Debye]; Reid, Prausnitz, & Poling, McGraw-Hill (1987) NBP !Default reference state 10.0 !Version number 1079 !UN Number :UN: other !Family :Family: ???? !Heating value (upper) [kJ/mol] :Heat: B1 !Safety Group (ASHRAE Standard 34, 2010) :Safety: 1S/O2S/c1-3-2 !Standard InChI String :InChi: RAHZWNYVWXNFOC-UHFFFAOYSA-N !Standard InChI Key :InChiKey: e9847540 (ammonia) !Alternative fluid for mixing rules :AltID: 7fad4b80 !Hash number from InChI Key :Hash: !The fluid files contain general information about the fluid in the first 15 to 20 lines, followed by sections for the ! equations of state, transport equations, and auxiliary equations. Equations of state are listed first. The NIST recommended ! equations begin with a hash mark (#). The secondary equations begin with the @ symbol. These symbols can be swapped to ! select a secondary equation as primary and the primary as secondary. The equation of state section also contains auxiliary ! equations for the ideal gas heat capacity or ideal gas Helmholtz energy. Below the equations of state (both primary and ! secondary) are the transport equations, first viscosity and then thermal conductivity. These are then followed by the ! secondary equations if available. The transport section also contains auxiliary equations required to calculate either the ! dilute gas state or the critical enhancement. At the end of the file are additional but not necessary auxiliary equations, ! including simple equations for the vapor pressure, saturated liquid and vapor densities, melting line (for some fluids), and ! sublimation line (for even fewer fluids). This section also contains the equations for dielectric constant and surface ! tension if available. The sections are divided by different symbols (these being _-+=^*~) to aid the eye in locating a ! particular section. Secondary equations are indented 10 spaces to avoid confusion with the NIST recommended equations. The ! end of the fluid file is marked with @END. Anything below that is ignored. ! compiled by E.W. Lemmon, NIST Physical and Chemical Properties Division, Boulder, Colorado ! 11-13-98 EWL, Original version. ! 01-31-02 EWL, Fit new equation of state based on data of Ihmels. ! 04-30-02 EWL, Update fit. ! 11-14-02 EWL, Update fit with new PVT data of Ihmels. ! 08-17-10 IDC, Add ancillary equations. ! 12-06-12 EWL, Add surface tension coefficients of Mulero et al. (2012). ! 03-11-13 MLH, Add ECS transport, estimation not std ref quality. ! 02-29-16 EWL, Add equation of state of Gao et al. (2016). ! 02-28-17 MLH, Revise transport. ________________________________________________________________________________ #EOS !---Equation of state--- FEQ !Helmholtz equation of state for sulfur dioxide of Gao et al. (2016). :TRUECRITICALPOINT: 430.64 8.078 !True EOS critical point [K, mol/L] (where dP/dD=0 and d^2P/dD^2=0 at constant T) :DOI: 10.1021/acs.jced.6b00195 ? ?``````````````````````````````````````````````````````````````````````````````` ?Gao, K., Wu, J., Zhang, P., and Lemmon, E.W., ? "A Helmholtz Energy Equation of State for Sulfur Dioxide," ? J. Chem. Eng. Data, 61:2859-2872, 2016. doi: 10.1021/acs.jced.6b00195 ? ?The equation of state is valid from the triple point temperature of 197.7 K to ? 523 K, with pressures up to 35 MPa and densities up to 25.3 mol/l. The ? uncertainties in density of the equation of state are 0.1 % in the liquid phase, ? 0.25 % in the vapor phase, and 1 % in the critical region. The uncertainty in ? vapor pressure is 0.2 % and the uncertainty in saturated liquid density is 0.2 % ? below 410 K. The uncertainty in isobaric heat capacity is 2 % between 200 K and ? 290 K. In the critical region, the uncertainties are higher for all properties ? except for vapor pressure. ? !``````````````````````````````````````````````````````````````````````````````` 197.7 !Lower temperature limit [K] 525.0 !Upper temperature limit [K] 35000.0 !Upper pressure limit [kPa] 25.42 !Maximum density [mol/L] CPP !Pointer to Cp0 model 64.0638 !Molar mass [g/mol] 197.7 !Triple point temperature [K] 1.6661 !Pressure at triple point [kPa] 25.41 !Density at triple point [mol/L] 263.137 !Normal boiling point temperature [K] 0.256 !Acentric factor 430.64 7886.6 8.078 !Tc [K], pc [kPa], rhoc [mol/L] 430.64 8.078 !Reducing parameters [K, mol/L] 8.3144598 !Gas constant [J/mol-K] 10 4 6 12 0 0 0 0 0 0 0 0 !# terms and # coefs/term for normal terms, Gaussian terms, and Gao terms 0.01744413 1.0 4. 0. !a(i),t(i),d(i),l(i) 1.814878 0.45 1. 0. -2.246338 0.9994 1. 0. -0.4602906 1. 2. 0. 0.1097049 0.45 3. 0. -0.9485769 2.907 1. 2. -0.8751541 2.992 3. 2. 0.4228777 0.87 2. 1. -0.4174962 3.302 2. 2. -0.002903451 1.002 7. 1. 1.64041 1.15 1. 2. 2. -1.061 -0.967 1.276 0.832 0. 0. 0. -0.4103535 0.997 1. 2. 2. -0.945 -2.538 0.738 0.69 0. 0. 0. -0.08316597 1.36 3. 2. 2. -1.741 -2.758 0.71 0.35 0. 0. 0. -0.2728126 2.086 2. 2. 2. -1.139 -1.062 0.997 0.961 0. 0. 0. -0.1075782 0.855 2. 2. 2. -1.644 -1.039 1.35 0.981 0. 0. 0. -0.4348434 0.785 1. 2. 2. -0.647 -0.41 0.919 0.333 0. 0. 0. eta beta gamma epsilon EXP[eta*(delta-epsilon)^2+beta*(tau-gamma)^2] #AUX !---Auxiliary function for Cp0 CPP !Ideal gas heat capacity function for sulfur dioxide of Gao et al. (2016). ? ?``````````````````````````````````````````````````````````````````````````````` ?Gao, K., Wu, J., Zhang, P., and Lemmon, E.W., 2016. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 1.0 8.3144598 !Reducing parameters for T, Cp0 2 2 0 0 0 0 0 !Nterms: polynomial, exponential, cosh, sinh 4.0 0.0 0.00007397 1.0 1.0875 783.0 1.916 1864.0 #AUX !---Auxiliary function for PX0 PX0 !Helmholtz energy ideal-gas function for sulfur dioxide of Gao et al. (2016). ? ?``````````````````````````````````````````````````````````````````````````````` ?Gao, K., Wu, J., Zhang, P., and Lemmon, E.W., 2016. ? !``````````````````````````````````````````````````````````````````````````````` 1 3 2 0 0 0 0 0 !Nterms: ai*log(tau**ti); ai*tau**ti; ai*log(1-exp(bi*tau)) 3.0 1.0 !ai, ti for [ai*log(tau**ti)] terms -4.541423325625578 0.0 !aj, ti for [ai*tau**ti] terms 4.4732288061807504 1.0 !aj, ti for [ai*tau**ti] terms 0.00007397 -1.0 1.0875 783.0 !aj, ti for [ai*log(1-exp(-ti/T)] terms 1.916 1864.0 #AUX !---Auxiliary function for PH0 PH0 !Ideal gas Helmholtz form for sulfur dioxide of Gao et al. (2016). ? ?``````````````````````````````````````````````````````````````````````````````` ?Gao, K., Wu, J., Zhang, P., and Lemmon, E.W., 2016. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 1 3 2 0 0 0 0 0 !Nterms: ai*log(tau**ti); ai*tau**ti; ai*log(1-exp(bi*tau)); cosh; sinh 3.0 1.0 !ai, ti for [ai*log(tau**ti)] terms -4.5414235721 0.0 !aj, ti for [ai*tau**ti] terms 4.4732289572 1.0 -0.0159272204 -1.0 1.0875 -1.8182240386 !aj, ti for [ai*log(1-exp(ti*tau)] terms 1.916 -4.3284413896 -------------------------------------------------------------------------------- @EOS !---Equation of state--- FE1 !Helmholtz equation of state for sulfur dioxide of Lemmon and Span (2006). ? ?``````````````````````````````````````````````````````````````````````````````` ?Lemmon, E.W. and Span, R., ? "Short Fundamental Equations of State for 20 Industrial Fluids," ? J. Chem. Eng. Data, 51(3):785-850, 2006. doi: 10.1021/je050186n ? ?see also: ? Ihmels, E.C., Lemmon, E.W., Gmehling, J., ? "An Equation of State and Compressed Liquid and Supercritical Densities for ? Sulfur Dioxide," ? Fluid Phase Equilib., 207:111-130, 2003. doi: 10.1016/S0378-3812(03)00004-9 ? ?The uncertainty in density of the equation of state ranges from 0.1% at low ? temperatures in the liquid and vapor to 0.5% at the highest temperatures. ? The uncertainty in heat capacities is 2%, and the uncertainty in vapor ? pressure is 0.4% at temperatures above 270 K. The uncertainty in vapor ? pressure increases at lower temperatures due to the lack of reliable ? experimental data. In the critical region, the uncertainties are higher ? for all properties except vapor pressure. ? !``````````````````````````````````````````````````````````````````````````````` 197.7 !Lower temperature limit [K] 525.0 !Upper temperature limit [K] 35000.0 !Upper pressure limit [kPa] 25.30 !Maximum density [mol/L] CP1 !Pointer to Cp0 model 64.0638 !Molar mass [g/mol] 197.7 !Triple point temperature [K] 1.66 !Pressure at triple point [kPa] 25.29 !Density at triple point [mol/L] 263.13 !Normal boiling point temperature [K] 0.2557 !Acentric factor 430.64 7884.0 8.195 !Tc [K], pc [kPa], rhoc [mol/L] 430.64 8.195 !Reducing parameters [K, mol/L] 8.314472 !Gas constant [J/mol-K] 12 4 0 0 0 0 0 0 0 0 0 0 !# terms and # coefs/term for normal terms, Gaussian terms, and Gao terms 0.93061 0.25 1. 0. !a(i),t(i),d(i),l(i) -1.9528 1.25 1. 0. -0.17467 1.5 1. 0. 0.061524 0.25 3. 0. 0.00017711 0.875 7. 0. 0.21615 2.375 1. 1. 0.51353 2.0 2. 1. 0.010419 2.125 5. 1. -0.25286 3.5 1. 2. -0.054720 6.5 1. 2. -0.059856 4.75 4. 2. -0.016523 12.5 2. 3. @AUX !---Auxiliary function for Cp0 CP1 !Ideal gas heat capacity function for sulfur dioxide. ? ?``````````````````````````````````````````````````````````````````````````````` ?Lemmon, E.W. and Span, R. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 1.0 8.314472 !Reducing parameters for T, Cp0 2 2 0 0 0 0 0 !Nterms: polynomial, exponential, cosh, sinh 4.0 0.0 0.000072453 1.0 1.062 775.0 1.9401 1851.0 @AUX !---Auxiliary function for PH0 PH1 !Ideal gas Helmholtz form for sulfur dioxide. ? ?``````````````````````````````````````````````````````````````````````````````` ?Lemmon, E.W. and Span, R. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 1 3 2 0 0 0 0 0 !Nterms: ai*log(tau**ti); ai*tau**ti; ai*log(1-exp(bi*tau)); cosh; sinh 3.0 1.0 !ai, ti for [ai*log(tau**ti)] terms -4.5328346436 0.0 !aj, ti for [ai*tau**ti] terms 4.4777967379 1.0 -0.01560058 -1.0 1.062 -1.799647037 !aj, ti for [ai*log(1-exp(ti*tau)] terms 1.9401 -4.2982537618 @EOS !---Equation of state--- FE2 !Helmholtz equation of state for sulfur dioxide of Polt (1987). ? ?``````````````````````````````````````````````````````````````````````````````` ?Polt, A., ? Zur Beschreibung der thermodynamischen Eigenschaften reiner Fluide ? mit "Erweiterten BWR-Gleichungen", ? Ph.D. Dissertation, Universitaet Kaiserslautern, Germany, 1987. ? !``````````````````````````````````````````````````````````````````````````````` 273.0 !Lower temperature limit [K] 523.0 !Upper temperature limit [K] 32000.0 !Upper pressure limit [kPa] 22.91 !Maximum density [mol/L] CP2 !Pointer to Cp0 model 64.066 !Molar mass [g/mol] 197.7 !Triple point temperature [K] 11.82 !Pressure at triple point [kPa] 23.0 !Density at triple point [mol/L] (unknown) 256.61 !Normal boiling point temperature [K] 0.23 !Acentric factor 430.65 7880.0 8.1946742 !Tc [K], pc [kPa], rhoc [mol/L] 430.65 8.1946742 !Reducing parameters [K, mol/L] 8.3143 !Gas constant [J/mol-K] 22 4 0 0 0 0 0 0 0 0 0 0 !# terms and # coefs/term for normal terms, Gaussian terms, and Gao terms 0.789407019882 3.0 0. 0. !a(i),t(i),d(i),l(i) -1.70449580056 4.0 0. 0. 1.15984637964 5.0 0. 0. -0.576307837294 0.0 1. 0. 2.49237283833 1.0 1. 0. -5.18115678632 2.0 1. 0. 3.20766081899 3.0 1. 0. -1.23636065893 4.0 1. 0. 0.0144419600938 0.0 2. 0. -0.153807055040 1.0 2. 0. 0.386324300525 2.0 2. 0. 0.292550313202 0.0 3. 0. -0.372445361392 1.0 3. 0. -0.063692433391 0.0 4. 0. 0.0986166451596 1.0 4. 0. -0.00216993783055 1.0 5. 0. -0.789407019882 3.0 0. 2. 1.70449580056 4.0 0. 2. -1.15984637964 5.0 0. 2. -0.480876182378 3.0 2. 2. 1.64910076886 4.0 2. 2. -1.33861069604 5.0 2. 2. @AUX !---Auxiliary function for Cp0 CP2 !Ideal gas heat capacity function for sulfur dioxide. ? ?``````````````````````````````````````````````````````````````````````````````` ?Polt, A., ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 1.0 64.066 !Reducing parameters for T, Cp0 5 0 0 0 0 0 0 !Nterms: polynomial, exponential, cosh, sinh 0.4021066 0.0 0.0008734857 1.0 -0.4596882e-6 2.0 -0.133284e-11 3.0 0.23785e-13 4.0 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ #TRN !---ECS Transport--- ECS !Extended Corresponding States model (Propane reference); fitted to very limited data for sulfur dioxide. :DOI: 10.6028/NIST.IR.8209 ? ?``````````````````````````````````````````````````````````````````````````````` ?Huber, M.L., "Models for the Viscosity, Thermal Conductivity, and Surface Tension ? of Selected Pure Fluids as Implemented in REFPROP v10.0," NISTIR 8209, 2018. ? doi: 10.6028/NIST.IR.8209 ? ?THERMAL CONDUCTIVITY ? The parameters for thermal conductivity were based in part on the data of: ? Kardos, A., "The Heat Conductivities of Various Liquids," Z. ges. Kalte-Ind., 41, 29-35, 1934. ? Baker, C.B. and de Haas, N., "Gas Thermal Conductivity Studies at High Temperature. III. Results for SO2," Phys. Fluids, 7:1400-1402, 1964. doi: 10.1063/1.1711394 ? ?The estimated uncertainty of thermal conductivity in the liquid phase along the saturation boundary is 5%, rising to 10% at 35 MPa. ? The estimated uncertainty of thermal conductivity in the gas phase is 5%. ? ?VISCOSITY ? The ECS parameters for viscosity were based in part on the data of: ? Hartl, R., Neueder, R., and Gores, H.J., "Temperature Dependence of Association Constants of LiAlCl4 in Liquid Sulfur Dioxide," Acta Chim. Slov., 56:109-114, 2009. ? Awbery, J.H. and Griffiths, E., "The Viscosities of Some Liquid Refrigerants," Proc. Phys. Soc., London, 48:372-80, 1936. ? Stewart, W.W. and Maass, "The Coefficient of Viscosity of Sulphur Dioxide over a Low Temperature Range," Can. J. of Research, 6(5):453-457, 1932. doi: 10.1139/cjr32-035 ? ?The estimated uncertainty of viscosity in the liquid phase along the saturation boundary is 5%, rising to 10% at 35 MPa. ?The estimated uncertainty of viscosity in the gas phase is 5%. ? !``````````````````````````````````````````````````````````````````````````````` 197.7 !Lower temperature limit [K] 525.0 !Upper temperature limit [K] 35000.0 !Upper pressure limit [kPa] 25.42 !Maximum density [mol/L] FEQ PROPANE.FLD VS1 !Model for reference fluid viscosity TC1 !Model for reference fluid thermal conductivity NUL !Large molecule identifier 1 !Lennard-Jones flag (0 or 1) (0 => use estimates) !from scaling R134a 0.4026 !Lennard-Jones coefficient sigma [nm] for ECS method 363.0 !Lennard-Jones coefficient epsilon/kappa [K] for ECS method 2 0 0 !Number of terms in f_int term in Eucken correlation, spare1, spare2 6.60505e-4 0. 0. 0. !Coefficient, power of T, spare1, spare2 7.47059e-7 1. 0. 0. !Coefficient, power of T, spare1, spare2 2 0 0 !Number of terms in psi (visc shape factor): poly,spare1,spare2 0.917778 0. 0. 0. !Coefficient, power of Tr, power of Dr, spare 0.0248405 0. 1. 0. !Coefficient, power of Tr, power of Dr, spare 2 0 0 !Number of terms in chi (t.c. shape factor): poly,spare1,spare2 1.38755 0. 0. 0. !Coefficient, power of Tr, power of Dr, spare -0.128721 0. 1. 0. !Coefficient, power of Tr, power of Dr, spare TK3 !Pointer to critical enhancement auxiliary function #AUX !---Auxiliary function for the thermal conductivity critical enhancement TK3 !Simplified thermal conductivity critical enhancement for sulfur dioxide of Perkins et al. (2013). ? ?``````````````````````````````````````````````````````````````````````````````` ?Perkins, R.A., Sengers, J.V., Abdulagatov, I.M., and Huber, M.L., ? "Simplified Model for the Critical Thermal-Conductivity Enhancement in Molecular Fluids," ? Int. J. Thermophys., 34(2):191-212, 2013. doi: 10.1007/s10765-013-1409-z ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 9 0 0 0 !# terms: CO2-terms, spare, spare, spare 1.0 1.0 1.0 !Reducing parameters for T, rho, tcx [mW/(m-K)] 0.63 !Nu (universal exponent) 1.239 !Gamma (universal exponent) 1.02 !R0 (universal amplitude) 0.063 !Z (universal exponent--not used for t.c., only viscosity) 1.0 !C (constant in viscosity eqn = 1/[2 - (alpha + gamma)/(2*nu)], but often set to 1) 0.167e-9 !Xi0 (amplitude) [m] 0.059 !Gam0 (amplitude) [-] 0.485e-9 !Qd_inverse (modified effective cutoff parameter) [m] 645.96 !Tref (reference temperature)=1.5*Tc [K] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #DE !---Dielectric constant--- DE5 !Dielectric constant model for SO2 of Harvey and Mountain (2017). :DOI: 10.1007/s10765-017-2279-6 ? ?``````````````````````````````````````````````````````````````````````````````` ?Harvey, A.H. and Mountain, R.D., ? "Correlations for the Dielectric Constants of H2S, SO2, and SF6," ? Int. J. Thermophys., 38:147, 2017. ? !``````````````````````````````````````````````````````````````````````````````` 197.7 !Lower temperature limit [K] 525.0 !Upper temperature limit [K] 0. ! 0. ! 450.0 25.0 1.0 !Reducing parameters for T and D 4 1 1 1 0 0 !Number of terms in dielectric constant model 4.09e-24 0.0 0.0 0. ! alpha (cm^3) 1.63308 0.0 0.0 0. ! mu (debye) 0.335 0.0 0.0 0. ! cu 2.516 0.0 0.0 0. ! cg 1. 0.0 1.018 0.75 ! f 1. 0.0 0.8972 0.98 ! g1 1. 0.0 0.5264 1.2 ! g2 #STN !---Surface tension--- ST1 !Surface tension model for sulfur dioxide of Mulero et al. (2012). :DOI: 10.1063/1.4768782 ? ?``````````````````````````````````````````````````````````````````````````````` ?Mulero, A., Cachadiņa, I., and Parra, M.I., ? "Recommended Correlations for the Surface Tension of Common Fluids," ? J. Phys. Chem. Ref. Data, 41(4), 043105, 2012. doi: 10.1063/1.4768782 ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 3 !Number of terms in surface tension model 430.64 !Critical temperature used in fit (dummy) 0.0803 0.928 !Sigma0 and n 0.0139 1.57 -0.0114 0.364 #PS !---Vapor pressure--- PS5 !Vapor pressure equation for sulfur dioxide of Gao et al. (2016). ? ?``````````````````````````````````````````````````````````````````````````````` ?Gao, K., Wu, J., Zhang, P., and Lemmon, E.W., 2016. ? ?Functional Form: P=Pc*EXP[SUM(Ni*Theta^ti)*Tc/T] where Theta=1-T/Tc, Tc and Pc ? are the reducing parameters below, which are followed by rows containing Ni and ti. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 430.64 7886.6 !Reducing parameters 5 0 0 0 0 0 !Number of terms in equation -7.303 1.0 1.9794 1.5 -2.078 2.2 -3.5446 4.7 0.51776 6.0 #DL !---Saturated liquid density--- DL1 !Saturated liquid density equation for sulfur dioxide of Gao et al. (2016). ? ?``````````````````````````````````````````````````````````````````````````````` ?Gao, K., Wu, J., Zhang, P., and Lemmon, E.W., 2016. ? ?Functional Form: D=Dc*[1+SUM(Ni*Theta^ti)] where Theta=1-T/Tc, Tc and Dc are ? the reducing parameters below, which are followed by rows containing Ni and ti. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 430.64 8.078 !Reducing parameters 5 0 0 0 0 0 !Number of terms in equation 7.2296 0.54 -16.928 0.88 29.832 1.23 -27.901 1.6 11.085 2.0 #DV !---Saturated vapor density--- DV3 !Saturated vapor density equation for sulfur dioxide of Gao et al. (2016). ? ?``````````````````````````````````````````````````````````````````````````````` ?Gao, K., Wu, J., Zhang, P., and Lemmon, E.W., 2016. ? ?Functional Form: D=Dc*EXP[SUM(Ni*Theta^ti)] where Theta=1-T/Tc, Tc and Dc are ? the reducing parameters below, which are followed by rows containing Ni and ti. ? !``````````````````````````````````````````````````````````````````````````````` 0. ! 10000. ! 0. ! 0. ! 430.64 8.078 !Reducing parameters 6 0 0 0 0 0 !Number of terms in equation -7.487 0.545 10.118 0.85 -13.608 1.2 -25.408 3.7 -42.04 7.5 -38.668 10.0 @END c 1 2 3 4 5 6 7 8 c2345678901234567890123456789012345678901234567890123456789012345678901234567890 0.4112 !Lennard-Jones coefficient sigma [nm] for ECS method 335.4 !Lennard-Jones coefficient epsilon/kappa [K] for ECS method