Instrumental Methods of Analysis (chm 303)

The emitted radiation is usually in the visible region and at right angles to the incident radiation; only visible rarely when absorbed radiation is of visible high energy (short wavelength) in U.V region is the emitted radiation in U.V region. Molecules at room temperature are in ground electronic state. It absorbs energy and goes to excited electronic state. The groups of lines represent vibrational state. The entire process takes place in a very short time (≈ 10 – 10 s). The absorption requires about 10 s while the collision takes about 10 s.