Fourier Transform Infrared (ft-ir) Spectroscopy Theory and Applications

Fourier Transform Infrared (FT-IR) Spectroscopy

Theory and Applications

THE ELECTROMAGNETIC SPECTRUM
INFRARED
GAMMA RAYS X RAYS UV VISIBLE

Introduction to FTInfrared Spectroscopy

• What is infrared spectroscopy?
• Theory of FT-IR
• FT-IR Advantages?
• New FT/IR4000-6000Series

What is Infrared?

• Infrared radiation lies between the visible and microwave portions of the electromagnetic spectrum.
• Infrared waves have wavelengths longer than visible and shorter than microwaves, and have frequencies which are lower than visible and higher than microwaves.
• The Infrared region is divided into: near, mid and far-infrared.
• Near-infrared refers to the part of the infrared spectrum that is closest to visible light and far-infrared refers to the part that is closer to the microwave region.
• Mid-infrared is the region between these two.
• The primary source of infrared radiation is thermal radiation. (heat)
• It is the radiation produced by the motion of atoms and molecules in an object. The higher the temperature, the more the atoms and molecules move and the more infrared radiation they produce.
• Any object radiates in the infrared. Even an ice cube, emits infrared.

What is Infrared? (Cont.)

Humans, at normal body temperature, radiate most strongly in the infrared, at a wavelength of about 10 microns (A micron is the term commonly used in astronomy for a micrometer or one millionth of a meter). In the image to the left, the red areas are the warmest, followed by yellow, green and blue (coolest).

The image to the right shows a cat in the infrared. The yellow-white areas are the warmest and the purple areas are the coldest. This image gives us a different view of a familiar animal as well as information that we could not get from a visible light picture. Notice the cold nose and the heat from the cat's eyes, mouth and ears.