ASTR 151 Lecture Notes - Lecture 15: Thermometer, Balmer Series, Lyman Series
Document Summary
Visible light photons transitions starting or ending at the 1st excited state (n=2) Uv photons transitions starting or ending at the ground state (n=1) More protons=more electrons=more complicated energy structure=more complicated spectral lines. More protons and electrons means different electrical structure of atom: different electron orbital energy levels. More electrons mean more transitions means more spectral lines. Each ionizations changes the energy structure: hence, each ion has its own set of spectral lines. The emission spectrum tells us about the composition of the nebula. A molecule is tightly bound group of atoms held together by interactions between their orbiting electrons. More ways to absorb or release energy. Still have electronic transitions: uv, visible, and near infrared lines. Molecular vibrations: bending and stretching of the chemical bonds. Molecular rotations: microwave and radio lines. Information that is contained in spectral lines: chemical composition, temperature, rotation state, radial velocity, density and pressure, magnetic field strength.
