Atomic and Molecular Aspects of Astronomical Spectra
  In the first section we present the atomic part where a C2+ atomic target was
prepared and used to generate theoretical data to investigate recombination
lines arising from electron-ion collisions in thin plasma. R-matrix method was
used to describe the C2+ plus electron system. Theoretical data concerning
bound and autoionizing states were generated in the intermediate-coupling
approximation. The data were used to generate dielectronic recombination data
for C+ which include transition lines, oscillator strengths, radiative
transition probabilities, emissivities and dielectronic recombination
coefficients. The data were cast in a line list containing 6187
optically-allowed transitions which include many C II lines observed in
astronomical spectra. This line list was used to analyze the spectra from a
number of astronomical objects, mainly planetary nebulae, and identify their
electron temperature. The electron temperature investigation was also extended
to include free electron energy analysis to investigate the long-standing
problem of discrepancy between the results of recombination and forbidden lines
analysis and its possible connection to the electron distribution.
  In the second section we present the results of our molecular investigation;
the generation of a comprehensive, calculated line list of frequencies and
transition probabilities for H2D+. The line list contains over 22 million
rotational-vibrational transitions occurring between more than 33 thousand
energy levels and covers frequencies up to 18500 cm-1. About 15% of these
levels are fully assigned with approximate rotational and vibrational quantum
numbers. A temperature-dependent partition function and cooling function are
presented. Temperature-dependent synthetic spectra for the temperatures T=100,
500, 1000 and 2000 K in the frequency range 0-10000 cm-1 were also generated
and presented graphically.
