G4StatMFMacroChemicalPotential.cc

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// Hadronic Process: Nuclear De-excitations
// by V. Lara
//
// Modification: 13.08.2025 V.Ivanchenko rewrite
 
#include "G4StatMFMacroChemicalPotential.hh"
#include "G4StatMFParameters.hh"
#include "G4StatMFMacroMultiplicity.hh"
#include "G4PhysicalConstants.hh"
#include "G4Pow.hh"
 
G4StatMFMacroChemicalPotential::G4StatMFMacroChemicalPotential()
{
  theMultip = new G4StatMFMacroMultiplicity();
  fSolver = new G4FunctionSolver<G4StatMFMacroChemicalPotential>(this, 100, 5.e-4);
}
 
 
G4StatMFMacroChemicalPotential::~G4StatMFMacroChemicalPotential()
{
  delete fSolver;
  delete theMultip;
}
 
void G4StatMFMacroChemicalPotential::Initialise(
                     const G4int anA, const G4int aZ,
                     const G4double kappa,
                     const G4double temp, 
                     std::vector<G4VStatMFMacroCluster*>* v)
{
  theA = anA;
  theZ = aZ;
  fKappa = kappa;
  fMeanTemperature = temp;
  fClusters = v;
}
 
G4double G4StatMFMacroChemicalPotential::CalcChemicalPotentialNu()
//  Calculate Chemical potential \nu
{
  G4Pow* g4calc = G4Pow::GetInstance();
  G4double CP = G4StatMFParameters::GetCoulomb();
 
  // Initial value for fChemPotentialNu 
  fChemPotentialNu = (theZ/(G4double)theA)*
    (8.0*G4StatMFParameters::GetGamma0() + 2.0*CP*g4calc->Z23(theA))
    - 4.0*G4StatMFParameters::GetGamma0();
        
  fSolver->SetIntervalLimits(0.5*fChemPotentialNu, 2*fChemPotentialNu);
  fSolver->FindRoot(fChemPotentialNu);
  return fChemPotentialNu;
}
 
G4double G4StatMFMacroChemicalPotential::CalcMeanZ(const G4double nu)
{
  CalcChemicalPotentialMu(nu);
  // This is important, the Z over A ratio for proton and neutron depends on the 
  // chemical potential Mu, while for the first guess for Chemical potential mu 
  // some values of Z over A ratio. This is the reason for that.
  
  G4double MeanZ = 0.0;
  G4int n = 0;
  G4int nn = (G4int)fClusters->size();
  nn = std::min(nn, theA);
  for (G4int i = 0; i < nn; ++i) {
    G4double x = (*fClusters)[i]->CalcZARatio(nu);
    MeanZ += (n++) * x * (*fClusters)[i]->GetMeanMultiplicity(); 
  }
  return MeanZ;
}
 
void G4StatMFMacroChemicalPotential::CalcChemicalPotentialMu(const G4double nu)
//  Calculate Chemical potential \mu
// For that is necesary to calculate mean multiplicities
{
  theMultip->Initialise(theA, fKappa, fMeanTemperature, nu, fClusters);
  fChemPotentialMu = theMultip->CalcChemicalPotentialMu();
  fMeanMultiplicity = theMultip->GetMeanMultiplicity();
}