Question

Describe the capabilities and limitations of Raman/ IR and why they are complementary techniques?

Answer 1

| 17. Speisazenom Capabilities Ramain pestroscopy Raman spectroscopy give ir spectroscopy is the structurral firopoort woted to catch typen of a molecule .. bood vibrations of By calculating the Rarrom ever rrebeshe. shifter Neni each robleelle Aya A has its characteristics which is arises due to kori stratech.ro inelastic saettering of frequeney and it incident photos by elections wes in notre res range. in atoms / moleerles This So it Raman is very croseto shift is toor catch luorique to each emolude useful to helps in molecute charrasteri-detect viro IR Zatim, spectroscopy lit also gives the complete picture of vibrational mode in fig fingerprint region 1500-15co em). Limitation Rarron signal is very Tweak signal. So, a pruch costly instrument- ation is required in Raman Spectroscopy liR spectroscopy is Ihreeful ority to those insleente which has Icharse in dipole resorent. But there arre rosny mores not having that capabilities These orre celles IR IP inostive. These molaswers cannot be detected by је

The complementarity Rasman and IR understood by a simple example The bond stretching modes of O=C=0 can be of coo co, are belon (1) Symmetric Stretching Asymmetric Stretching o= =o a IR active Raman Inactive IR inactive Raman active Reason - IR records change in dipole moment which is related to change in bond length and Raman. records change of polarizibility which is related to the bord strength means how strongly is attached electrons are attached to the nuclei or in simple terme rolune toto change of the molecule, In symmetric stretching bond length increases so dipole moment changes & IR signal But molecule is not polarizable as both oxygen atoms are equidistant from nuclei means synimetrie distribution of electrons over nuclei. Raman . Inactive Inactiva . The case is reverse in assymmetric stretching mode. Such IR is a complementary to Raman.