Infrared spectroscopy is not the only method of studying molecular vibrational spectra. PAHs possess very characteristic UV absorbance spectra. FTIR is a method of measuring infrared absorption and emission spectra. Tattoo pigments have specific light absorption spectra. The absorption spectra of carbon and hydrogen minimize heating. The Bohr model was able to explain the emission and absorption spectra of hydrogen. The absorption spectra of the three systems overlap, and combine to cover the visible spectrum. This is typical of the infrared spectra of heteronuclear diatomic molecules. There are a wide range of experimental approaches for measuring absorption spectra. The absorption spectra of oxyhemoglobin and deoxyhemoglobin differ. The irregulars generally have featureless visible and near infrared spectra dominated by water absorption bands. NMR spectra display less distortion than lower frequency spectra. The final spectrum is obtained by averaging over all the tapered spectra. This redshift range was in clear disagreement with the results from studying quasar spectra. They are characteristic fragments observed in EI-mass spectra of ketones.