GeochemistryActivityCalculators Namespace Reference

Calculators to compute activity coefficients. More...

Functions
Real	log10ActCoeffDHBdot (Real charge, Real ion_size, Real sqrt_ionic_strength, Real A, Real B, Real Bdot)
	log10(activity coefficient) according to the Debye-Huckel B-dot model More...
Real	log10ActCoeffDHBdotNeutral (Real ionic_strength, Real a, Real b, Real c, Real d)
	log10(activity coefficient) for neutral species according to the Debye-Huckel B-dot model More...
Real	lnActivityDHBdotWater (Real stoichiometric_ionic_strength, Real A, Real atilde, Real btilde, Real ctilde, Real dtilde)
	ln(activity of water) according to the Debye-Huckel B-dot model More...
Real	log10ActCoeffDHBdotAlternative (Real ionic_strength, Real Bdot)
	log10(activity coefficient) alternative expression that is sometimes used in conjunction with the Debye-Huckel B-dot model More...
Real	log10ActCoeffDavies (Real charge, Real sqrt_ionic_strength, Real A)
	log10(activity coefficient) according to the Davies model More...

Detailed Description

Calculators to compute activity coefficients.

Function Documentation

lnActivityDHBdotWater()

Real GeochemistryActivityCalculators::lnActivityDHBdotWater	(	Real	stoichiometric_ionic_strength,
		Real	A,
		Real	atilde,
		Real	btilde,
		Real	ctilde,
		Real	dtilde
	)

ln(activity of water) according to the Debye-Huckel B-dot model

Definition at line 54 of file GeochemistryActivityCalculators.C.

Referenced by TEST(), and GeochemistryActivityCoefficientsDebyeHuckel::waterActivity().

{
  if (stoichiometric_ionic_strength <= 0.0)
    return 0.0; // guard against unphysical inputs that might occur during a Newton process
  const Real bhat = 1.0 + atilde * std::sqrt(stoichiometric_ionic_strength);
  const Real inner = bhat - 2.0 * std::log(bhat) - 1.0 / bhat;
  const Real outer = 1.0 -
                     A * GeochemistryConstants::LOGTEN / Utility::pow<3>(atilde) /
                         stoichiometric_ionic_strength * inner +
                     0.5 * btilde * stoichiometric_ionic_strength +
                     2.0 * ctilde * Utility::pow<2>(stoichiometric_ionic_strength) / 3.0 +
                     0.75 * dtilde * Utility::pow<3>(stoichiometric_ionic_strength);
  return -2.0 * stoichiometric_ionic_strength * outer / GeochemistryConstants::MOLES_PER_KG_WATER;
}

log10ActCoeffDavies()

Real GeochemistryActivityCalculators::log10ActCoeffDavies	(	Real	charge,
		Real	sqrt_ionic_strength,
		Real	A
	)

log10(activity coefficient) according to the Davies model

Definition at line 44 of file GeochemistryActivityCalculators.C.

Referenced by TEST().

{
  if (sqrt_ionic_strength <= 0.0)
    return 0.0; // guard against unphysical inputs that might occur during a Newton process
  return -A * Utility::pow<2>(charge) *
         (sqrt_ionic_strength / (1.0 + sqrt_ionic_strength) -
          0.3 * Utility::pow<2>(sqrt_ionic_strength));
}

log10ActCoeffDHBdot()

Real GeochemistryActivityCalculators::log10ActCoeffDHBdot	(	Real	charge,
		Real	ion_size,
		Real	sqrt_ionic_strength,
		Real	A,
		Real	B,
		Real	Bdot
	)

log10(activity coefficient) according to the Debye-Huckel B-dot model

Definition at line 17 of file GeochemistryActivityCalculators.C.

Referenced by GeochemistryActivityCoefficientsDebyeHuckel::buildActivityCoefficients(), and TEST().

{
  if (sqrt_ionic_strength <= 0.0)
    return 0.0; // guard against unphysical inputs that might occur during a Newton process
  return -A * Utility::pow<2>(charge) * sqrt_ionic_strength /
             (1.0 + ion_size * B * sqrt_ionic_strength) +
         Bdot * Utility::pow<2>(sqrt_ionic_strength);
}

log10ActCoeffDHBdotAlternative()

Real GeochemistryActivityCalculators::log10ActCoeffDHBdotAlternative	(	Real	ionic_strength,
		Real	Bdot
	)

log10(activity coefficient) alternative expression that is sometimes used in conjunction with the Debye-Huckel B-dot model

Definition at line 36 of file GeochemistryActivityCalculators.C.

Referenced by GeochemistryActivityCoefficientsDebyeHuckel::buildActivityCoefficients(), and TEST().

{
  if (ionic_strength <= 0.0)
    return 0.0; // guard against unphysical inputs that might occur during a Newton process
  return Bdot * ionic_strength;
}

log10ActCoeffDHBdotNeutral()

Real GeochemistryActivityCalculators::log10ActCoeffDHBdotNeutral	(	Real	ionic_strength,
		Real	a,
		Real	b,
		Real	c,
		Real	d
	)

log10(activity coefficient) for neutral species according to the Debye-Huckel B-dot model

Definition at line 27 of file GeochemistryActivityCalculators.C.

Referenced by GeochemistryActivityCoefficientsDebyeHuckel::buildActivityCoefficients(), and TEST().

{
  if (ionic_strength <= 0.0)
    return 0.0; // guard against unphysical inputs that might occur during a Newton process
  return a * ionic_strength + b * Utility::pow<2>(ionic_strength) +
         c * Utility::pow<3>(ionic_strength) + d * Utility::pow<4>(ionic_strength);
}