Gibbs Project

H2O

Contents

This page contains the summary most important results. For additional information about reproduction of published simulation data click here.
SPC water
Parameters for the SPC model: q(O)=-0.82 e, q(H)=0.41 e, alpha=109.47o, r(OH)=1 A, epsilon(O)=78.21 K, sigma(O)=3.167 A, m(H)=1.0079 g/mol, m(O)=15.9994 g/mol.
SPCE water
Parameters for the SPCE model: q(O)=-0.8476 e, q(H)=0.4238 e, alpha=109.47o, r(OH)=1 A, epsilon(O)=78.21 K, sigma(O)=3.166 A, m(H)=1.0079 g/mol, m(O)=15.9994 g/mol. The harmonic bond angle interaction of the SPCE model is not taken into account.
Phase envelope
Several points on the phase envelope were calculated by GEMC-NVT runs with constant volume changes and compared with results of de Pablo et al., J. Chem. Phys. 93, 7355-7359 (1990) (SPC water) and Alejandre et al., J. Chem. Phys. 102, 4574-4583 (1990) (SPCE water) and experimental data. The SPC model gives very good agreement with the experimental data for the density of the vapor phase while the vapor density is underestimated by the SPCE model. The liquid density is underestimated by both, the SPC and the SPCE model, where the results given by the SPCE model are closer.

  • rho(T)

    • Vapor pressure
    Vapor pressure calculations for SPC and SPCE water were done at different temperatures and compared with experimental data. The results for SPCE water were also compared with an equation of state (Guissani and Guillot, J. Chem. Phys. 98, 8221 (1993)). Averaging was done over intervals between 0.75*106 and 1.5*106 configurations. The results obtained by using the SPC model are in very good agreement with the experimental data, while the SPCE model underestimates the vapor pressure due to its higher attractivity.

  • log pS(1/T)
  • pS(T)
    Note: Point pSPCES(T=328 K) was averaged over an interval with no accepted volume changes.

    • rho(T), pS(T) SPC

    T(K)

    rholiq (g/cm3)

    rhovap (g/cm3)

    rholiq,exp (g/cm3)

    rhovap,exp (g/cm3)

    pS(bar)

    pSexp(bar)

    373

    0.912(5)

    0.00077(5)

    0.958

    0.0006

    1.232(51)

    1.013

    423

    0.813(16)

    0.0022(3)

    0.917

    0.0025

    4.14(52)

    4.760

    473

    0.781(17)

    0.0088(17)

    0.865

    0.0079

    17(3)

    15.55

    523

    0.642(12)

    0.0233(38)

    0.799

    0.02

    40(6)

    39.78

    rho(T), pS(T) SPCE

    T(K)

    rholiq (g/cm3)

    rhovap (g/cm3)

    rholiq,exp (g/cm3)

    rhovap,exp (g/cm3)

    pS(bar)

    pS(bar)

    328

    0.962(1)

    0.00004(4)

    0.985

    0.0001

    0.065(41)

    0.157

    373

    0.927(8)

    0.00031(7)

    0.958

    0.0006

    0.53(12)

    1.013

    423

    0.888(10)

    0.00092(5)

    0.917

    0.0025

    1.72(13)

    4.760

    479

    0.818(12)

    0.0043(7)

    0.856

    0.009

    9(1)

    17.60

    523

    0.768(6)

    0.0132(3)

    0.799

    0.02

    15(5)

    39.78

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    Last modified by Johannes, July 31st 1996
    Page created by Johannes, March 16th 1996