Compilation, Calculation and Validation
Of Fundamental Data for Diatomic Molecules
Ursel Fantz and Dirk Wünderlich
Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2,
85748 Garching, Germany
The compilation of atomic and molecular data for plasma edge modelling is focussed on
atomic and molecular hydrogen (and its isotopomeres) and on hydrocarbon species, i.e. CH
and C2 molecules. Franck-Condon factors and transition probabilities are calculated with the
code TraDiMo on the basis of potential curves and dipole transition moments compiled from
literature. The already available data set for transitions in hydrogen molecules has been
extended by calculating transitions from the hydrogen molecule to the ground state of the
molecular hydrogen ion. Vibrationally resolved cross sections and rate coefficients for
electron impact collisions are compiled from literature and, if not available, calculated using
the code IPProg, which is based on the Impact Parameter method. Data sets for CH and C2 will
be presented, which are also the basis for collisional radiative modelling using the flexible
code Yacora. The analysis of populating and depopulating processes allows for an assessment
of their relevance in plasma edge, e.g. calculations of photon emissivity coefficients. In order
to address the importance of heavy particle collisions in dissociation modelling of
hydrocarbons, Yacora calculations with and without taking into account heavy particle
collisions will be shown. Calculated population densities and particle densities are validated
by dedicated experiments in laboratory plasmas and in the plasma edge of fusion experiments.