Materials Similar to Hydrogen Spectrum, Mass of the Deuteron

• 48%: Helium Spectrum Analysis
• 37%: A Spectral Analysis of Laser Induced Fluorescence of Diatomic Iodine
• 36%: Doppler Free Laser Spectroscopy
• 36%: Electron Paramagnetic Resonance
• 36%: X-Ray Fluorescence (XRF) spectrometry for materials analysis and discovering "the atomic number"
• 34%: Doppler-free Laser Spectroscopy