Modelo de energía libre para gases no-ideales

ROHRMANN, R. D.; COCA, SEBASTIÁN

Capilla del Monte, Córdoba, Argentina

Congreso; Reunión de la Asociación Argentina de Astronomía; 2006

Observatorio Astronómico de la UNC

A gas mixture composed of hydrogen, helium, carbon, nitrogen and oxigen is studied at temperatures higher than 6000 K using the free energy minimization method. We essentially follow the well-known occupation probability formalism based on the chemical picture in which bound states are considered as composite particles. The chemical equilibrium is evaluated taking into account interactions between neutral-neutral and neutral-charged particles. The adopted free energy model is accurate at densities up to 0.01 g/cc and yields convergent internal partition functions, as required in studies of stellar atmospheres and circumstellar envelopes. Presently, the numerical code includes 3334 energy levels of atoms and ions. The inclusion of composite molecules in the code is in progress.