atomic lines
- finally hydrogen (H)
- simplest atom -- one electron orbiting one proton
- most abundant atom in the universe
- part of water (H2O) and organic molecules
- very simple visible spectrum (in fact the simplest!)
- 3 lines -- red (656 nm), blue (486 nm) and violet (436 nm)
- We see that the lines are characteristic of the atom
- all H atoms have exactly the same spectrum
- no two different atoms have the same spectra
- lines are “fingerprint” of atoms present
- If I had a mixture of H and He atoms -- the spectrum would show lines from each
- by measuring the strength of each line, I could tell how much H and He was present
- spectrometers permit analysis of line spectra and, hence, chemical composition from far distant objects