Summary of our Report *Infrared Spectroscopy- is thespectroscopythat deals with theinfrared region of the electromagneticspectrum, that is light with a longer wavelength and lower frequency than visible light. - It also the measurement of the wavelength and intensity of the absorption of mid-infrared light by a sample. The wavelength of infrared absorption bonds is characteristic of specific types of chemical bonds it can either identify organic or organometallic molecules. Theory of Infrared Absorption Spectroscopy- for a molecule to absorb IR, the vibrations and rotations within a molecule must cause a net change in the dipole moment of the molecule. Electrical field of the radiation interacts with fluctuations in the dipole moment of the molecules. If the frequency of the radiation matches the vibrational frequency of the molecule then the radiation will be absorbed. Rotational transitions are little use in spectroscopist because it is quantized and absorptions of IR by gases yields line spectra. If there are liquid or solids in the spectra, the line broaden into a continuum due to molecular collisions and other interactions. If a molecule is in an excited vibrational state will have a rotational energy and can lose energy in a transition. The total energy content of the molecule is given by the sum of the vibrational and rotational energies. For a molecule in a specific vibrational and rotational state, denoted by the pair of quantum numbers (v, J). Molecular Vibrations- In order to predict equilibrium stable-isotope fractionations, it is necessary to know the characteristic frequencies of molecular vibrations. Because vibrational frequency in a molecule changes when a heavy isotope is substituted for a light one. Frequencies are most commonly measured with infrared or Raman spectroscopy. Quantum Treatment of Vibrations- Transitions in vibrational energy levels can be brought about by absorption of radiation, If the radiation exactly matches the difference in energy levels between the vibrational quantum then it will cause a fluctuation to the dipole. Infrared spectrophotometer- is an instrument that passes infrared light through an organic molecule and produces a spectrum that contains a plot of the amount of light transmitted on the vertical axis against the wavelength of infrared radiation on the horizontal axis. Infrared spectra- the absorption peaks point downward because the vertical axis is the percentage transmittance of the radiation through the sample. Infrared Spectrophotometer- how does it work? - When the laser is fired, the mirror will reflect the light into the beam splitter which the light of the laser splits into two. Then the beams will scan the sample passes through them, gets reflected by mirrors again and beams collide with the help of the focusing lens and becomes one goes to the notch filter. And you can see your sample data in your spectrometer.