summary of spectroscopy with classification

1. Spectroscopy and its Classification
Presented By
Dr. Ved Nath Jha
Institute of Applied Sciences
Mangalayatan University, Aligarh

2. Spectroscopy
 Wavelength of emitted EM Wave is the function of
the interaction between the incident EM Wave
and matter.
 Spectral analysis is the investigation and
measurement of Spectra.
 Intensity of light variation with wavelength gives
spectrum

3. Classification of Spectroscopy
On the Basis of Structure
of Matter used
On the Basis of EM Wave

4. Matter used and Types of Spectroscopy
 Atomic Spectroscopy : It is related to electronic
transition
 Molecular Spectroscopy: It is based on the
concept of combination of atoms as a molecule
leads to the unique energy states, whereas the
electron spin, molecular vibration and molecular
rotation that make the collective motion of the
atomic nuclei are important.
 Development of molecular spectroscopy gives the
Maser and Laser.

5. Classification of Spectroscopy on the
basis of EM Wave characteristics
Absorption Spectroscopy
Scattering Spectroscopy
Emission Spectroscopy

6. Absorption Spectroscopy
 Lambert’s Law A = log10 (Io/I) and A = ∈cL where A is
absorbance, ∈= molar absorptivity, c= concentration
of given substance, L= path travelled in the sample,
Io = incident light intensity and I= transmitted
intensity. Therefore
 (Io/I) = transmittance or reflectance
 Amount of light absorbed by the substance is directly
proportional to the path travelled through the sample
and concentration of sample.
 It is for gaseous or liquid sample

7. Application of Absorption Spectroscopy
 Most of molecules or ions absorbs energy in
the uv or visible light i.e. atomic
spectroscopy.
 Chemical analysis
 Remote sensing
 Infrared gas analyzer distinguish between
nitrogen, oxygen and pollutants.

8. Absorption Spectroscopy
 Absorption occurs only when the energy of the
radiation matches the difference in the energy
between two energy levels of the sample atom.
 Electronic Transition due to absorbed energy
 Fourier Transform Spectroscopy
 IR Spectroscopy
 NMR spectroscopy(Radio Wave)

9. Scattering Spectroscopy
 Amount of light that a sample substance scatters at
certain wavelength.
 Scattering is much faster process than emission and
absorption
 Raman Spectroscopy
 Neutron Spectroscopy
 Reflection spectroscopy
 Mass spectroscopy: Spread the atomic and
molecular components in the sample as per their
masses and detect the sorted componnents.

10. Emission Spectroscopy
It is mainly for the solid
Based on emitted radiation and
particles.
Each element emits different
amount of energy and generally
has unique emission level.

11. Application of Emission spectroscopy
 It is produced by the heat or electric arc
 It is used to analyze the metallic elements in the solid sample. So used in
metal casting facility.

12. Spectroscopy of emitted wavelength
 It is Photoluminescence either gives Fluorescence or Phosphorescence.
 Gamma ray spectroscopy: measures gamma ray photon emitted by the
nucleus, quick and non destructive process. Nuclear Spectroscopy.
 X ray : ionize the atoms and makes transition of inner electrons in atom.
 UV/VIS : transition of middle and valence electron of atom.
 NIR/IR: Molecular vibration
 THz/Micro: Molecular rotation
 RF: Slow process of Spin of electron and nucleus or low energy process of
nuclear transition. NMR,ESR.

13. Emitted Particle based Spectroscopy
Electron Spectroscopy: Analysis of the
energy of the emitted electrons like
emission on photo-electrons.
Acoustic Spectroscopy: Emitted /
radiative pressure wave by the
macroscopic vibration of sample
emitted phonons.

14. Classification of Spectroscopy at a glance
 Matter structure
 Based Absorption
 Scattering

 Emission

15. Summary
Spectroscopy may be defined on
the basis of structure of sample
used, energy of light used and
behaviour of sample for the
specific light.

19. Thanksgiving