L4 Rich: raman spectroscopy Flashcards
what happens with light during Raman spectroscopy?
most of the light is absorbed and transmitted but some is scattered.
How can scattering of the light be observed?
It can be observed at a right angle to the incident beam
when scattering frequency is equal to incident frequency it is known as?
Rayleigh scattering
1% of scattered intensity occurs at a different frequency to the incident frequency.what is this called?
Raman scattering
what is Raman interactions dependent on?
existence of polarisable bonds
are larger atoms more polarisable?
yes
what can be used as a solvent tin Raman spectroscopy?
water
whats the rule of mutual exclusion when there is centre of symmetry?
If a molecule has a centre of symmetry then Raman active vibrations are infrared inactive and vice versa.
whats the rule of mutual exclusion when there is no centre of symmetry?
If there is no centre of symmetry, some vibrations may be both Raman and infrared active
Vibrations with a change in dipole moment give ___ _____
IR bands
Highly ____ bonds ____ intense IR bands
polar
intense
Highly polar bonds give ____ spectra of ____ intensity
Raman
Low
what samples can be used with RS?
gas, liquid, solid
is RS qualitative or quantitative?
mainly qualitative
is RS destructive?
no