Some more or less important physical features of PHOENIX are:

  • 1D plane parallel/spherical symmetric or 3D using different geometries radiative transfer
  • static or (up to relativistic) expanding media
  • the radiative transfer equation is solved using operator splitting
  • multilevel NLTE calculations for atoms with a total of more than 10000 levels and 100000 primary lines
  • the NLTE rate equations are solved using operator splitting techniques
  • usage of four atomic databases with NLTE transitions: CHIANTI Version 3 and 4, APED (ATOMDB) and the primary PHOENIX database
  • line blanketing and background opacities are included by design
  • over 650 species in the EOS including atoms, ions, molecules and grains
  • depth dependent Voigt profiles for Stark and van der Waals broadening
  • dynamical opacity sampling (dOS) of about 42 Million atomic lines and over 550 Million (and growing) molecular lines (more than 10GB worth of data)
  • spectra can be calculated for any desired resolution (standard are 20000 to 500000 wavelength points spread from the UV to the radio)
  • ... and more ..


PHOENIX is a parallelized Fortran 95 code with parts written in C (I/O) and C++ (high precision arithmetic using the QD library). The parallel computing is implemented using MPI (and partially openMP), for example Open MPI.