VIBRATIONAL SPECTROSCOPY - 2024/2025

Identify the bonds which will produce strong absorptions in the IR region of the electromagnetic spectrum.
I. C-O bond
II. C=C bond
III. C=O bond

• I and II only
• I and III only
• II and III only
• I, II and III

What part of the atom or molecule does infrared radiation affect

• the nucleus
• the electrons
• the  bonds
• the charge

The independent variable on an IR spectra is 

• wave length 
• wave number
• frequency squared
• transmission

The greater the polarity of a bond the_______________its IR absorption

• weaker
• stronger
• more charged
• smaller the wavenumber

 Mass of attached atoms affect the absorbance of the bond

• True
• False

What is Raman spectroscopy used for?

• Raman spectroscopy is used for measuring temperature changes.

• Raman spectroscopy is used for material characterization, chemical analysis, and identifying molecular structures.

• Raman spectroscopy is utilized for sound wave analysis.

• Raman spectroscopy is primarily used for visual art restoration.

Describe the basic principle of Raman spectroscopy.

• Raman spectroscopy analyzes molecular vibrations by measuring inelastic scattering of light.

• Raman spectroscopy measures the absorption of light by molecules.

• Raman spectroscopy is used to analyze electrical conductivity in materials.

• Raman spectroscopy detects changes in temperature by measuring light intensity.

How does Raman spectroscopy differ from infrared spectroscopy?

• Raman spectroscopy is limited to solid samples, while infrared spectroscopy can analyze gases and liquids.

• Raman spectroscopy requires a sample to be in a vacuum, whereas infrared spectroscopy does not.

• Raman spectroscopy measures absorption of visible light, while infrared spectroscopy uses inelastic scattering.

• Raman spectroscopy uses inelastic scattering of light, while infrared spectroscopy measures absorption of infrared light.

What types of samples can be analyzed using Raman spectroscopy?

• Only solids and liquids

• Solids, liquids, gases, and biological materials.

• Only gases and biological materials

• Only organic compounds

What is the difference between Stokes and anti-Stokes scattering?

• Stokes scattering involves energy gain (longer wavelength), while anti-Stokes scattering involves energy loss (shorter wavelength).

• Stokes scattering involves energy loss, while anti-Stokes scattering involves energy gain.

• Both Stokes and anti-Stokes scattering result in no change in energy.

• Stokes scattering occurs only in gases, while anti-Stokes occurs in liquids.