Raman Spectroscopy (Exam 3)

Question 1

What is the difference between Rayleigh (elastic) and Raman (inelastic) scattering?

Answer 1

Rayleigh - no energy change

Raman - energy change

Question 2

What are the 2 types of Raman scattering, and what is the difference?

Answer 2

Anti-stokes - decreased wavelength

Stokes - increased wavelength

Question 3

What is the difference between Raman active and IR active?

Answer 3

Raman - change in polarizability

IR - change in dipole

Question 4

What is the main use of Raman spectroscopy?

Answer 4

Complement to IR in that it detects functional groups

Question 5

What is the difference in how functional groups are detected in Raman and IR spectroscopy?

Answer 5

Raman - emphasizes aromatic cmpds & carbon backbones

IR - emphasizes polar functional groups

Question 6

What is the purpose of a monochromator?

Answer 6

To transmit light at a single wavelength

Question 7

What is the purpose of the optical filter in Raman spectroscopy?

Answer 7

To remove Rayleigh scattered light

Question 8

What is the most common approach to the characterization of forensics samples (besides using the reference spectrum of a known source)?

Answer 8

Using a spectral library