Instrumental Methods of analysis

Module VI: Instrumental Methods of analysis
Introduction; Principles of spectroscopy; Laws of absorbance
UV: Principle, Instrumentation and Application
IR: Principle, Instrumentation and Application
NMR: Principle, Instrumentation and Application

By looking at the EM spectrum of a substance, we can learn about it. Light tends to interact with molecules and atoms when it scatters or passes through matter. Since atoms and molecules have their own resonance frequencies, they interact directly with light waves that have the same frequencies. When excited atoms and molecules crash into each other, they give off light at a certain set of frequencies. This leads to another thing: a line spectrum. Here, only light with wavelengths that are far apart is made. The spectrum is also not a single line. Instead, it is made up of a set of lines called emission lines.

When light with continuous wavelengths passes through a low-density material, the atoms and molecules of that material will absorb light waves with the same set of characteristic frequencies. This makes the absorption spectrum, which is a spectrum that is almost continuous but has some lines missing.