ASTRO-110 Lecture Notes - Lecture 6: Electric Light, Absorption Spectroscopy, Continuous Spectrum
9 Sep 2020
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Document Summary
An atom contains an electron cloud with a nucleus at its centre, the nucleus contains protons and neutrons. Atomic number = # protons in nucleus, atomic mass number = # of protons + neutrons. Isotopes (same amount of protons, different number of neutrons. Molecules consist of two or more atoms. Phases of same material behave differently because of differences in chemical bonds. Ionization: stripping of electrons, changing atoms into plasma. Evaporation: breaking of flexible chemical bonds, changing liquid into gas. Melting: breaking of rigid chemical bonds, changing solid into liquid. Each type of atom has a unique spectral fingerprint. Observing the fingerprints in a spectrum tells us which kinds of atoms are present. The large numbers of vibrational and rotational energy levels can make the spectra of molecules very complicated. Many of these molecular transitions are in the infrared part of the spectrum. Nearly all large or dense objects emit thermal radiation, including stars, planets, you .
