Polarimetry Ashis Kumar Podder

Definition Polarimetry is a sensitive, nondestructive technique that measures the rotation of plane polarized light by inorganic and organic compounds.

There are two general regions in the infrared spectrum, namely: 1.Group frequency region: having a wavelength ranging from 2.5 to 8.0 µ and a wave number from cm -1 2.Fingerprint region: having a wavelength ranging from µ and a wavenumber from cm -1 IR regions

Theory of IR light absorption: 1.Stretching and 2.Bending vibrations

Infrared Group Analysis The four primary regions of IR spectrum 4000 cm cm cm cm cm -1 Bonds to H O-H single bond N-H single bond C-H single bond Triple bonds C ≡ C C ≡ N Double bonds C=O C=N C=C Single Bonds C-C C-N C-O Fingerprint Region

Serial no. Functional group Characteristic Absorption (s) (cm -1 ) Identified in (cm -1 ) 1SO 2 stretching Aromatic C = C bending1700 – Ketone C = O stretch1750 – Saturated C – H stretch2950 – Unsaturated C – H stretch Secondary N – H stretch3500 – O-H stretching3550 –

Infrared (IR) spectroscopy deals with the interaction between a molecule and radiation from the IR region of the EM spectrum (IR region = cm -1 ). In general terms it is convenient to split an IR spectrum into two approximate regions: A cm -1 known as the functional group region, most of the information that is used to interpret an IR spectrum is obtained from this region and B. < 1500 cm -1 known as the fingerprint region usually contains a very complicated series of absorptions