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CHAPTER 2 :check: - Coggle Diagram
CHAPTER 2 :check:
Factor affecting the width of spectral lines
Collision Broadening
Doppler Broadening
Heisenburg Uncertainty Principle
The Intensity of spectral lines
The transition probability
Rules to define transition
Define conditions for which transition dipole moment is nonzero.
Determined by quantum mechanics.
Not all transitions are possible (allowed)
Gross selection rules-specify general features a molecule must have in order for a spectrum to
be observed.
Specific selection rules - define allowed transitions in terms of changes in
quantum numbers
The population
Boltzman distribution
The concentration or path length
Beer-Lambert law
a sample is absorbing energy from a beam of radiation, the more sample
the beam traverses, the more energy will be absorbed from it.
Characterisation of Electromagnetic Radiation
Spectroscopy is the study of interaction of electromagnetic waves and matter
Basic element of practical spectroscopy
Absorption instruments
sample
modulator
white source
analyzer
detector
Emission Instrument
sample
analyzer
modulator
detector
excitation
Units
wavelength
in infra-red region measured micrometers
in visible and uv region measured in nanometers
in microwave measured in cm/mm
wavenumber expressed in cm-1
The Quantisation of energy
Energy is quantised: rotational, vibrational and other energies
PLANK'S EQUATION
∆ E = hν
Signal to noise ratio
to decrease noise :question:
use narrower slit
noise must lesser then signals