Astronomy Physics Astronomy, Astrophysics and Cosmology Astrophysics Cosmology Extraterrestrial Physics, Space Sciences History and Philosophical Foundations of Physics Astronomy, Observations and Techniques Atomic and Molecular Structure and Spectra Atomic structure Atomic/Molecular Structure and Spectra Atoms Atoms and Molecules in Strong Fields, Laser Matter Interaction Atoms and Molecules in Strong Fields, Plasma Physics Fluid- and Aerodynamics Fluids Gases History History of Science Matter Molecular structure Observations Observations, Astronomical Space sciences Spectra Μοριακή δομή Πλάσμα (Ιονισμένα αέρια)