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Spectroscopy is…?
Spectroscopy is the examination or viewing of colour.
Purpose of spectroscopy
Qualitative/quantitative cognition of
matter and follow time scaled change of matter.
What is a spectrum
Representation of one intensity like-quantity as a function of an energy-like quantity
What is a continuous emission spectrum?
Shows a glowing hot solid from a liquid source
What is an emission line-type spectrum
Shows a hot rarefied gas at high pressure
What is absorption line-type spectrum
Absorption of a cooler gas
The concept of absorption is?
When an electron in ground state is transmitted enough energy to excite it a certain level called excited state
How does light in a material lose its intensity
When it is propagated
Lambert-Beer law?
I= I0 e- E(wavelength)cx
What does Lambert-Beer law explain?
Decrease of light intensity in dilute solutions
Absorbance is…?
Negative logarithm of light leaving the solution (I)
Absorbance formula?
A = E(wavelength)cx
On what does light absorption depend ?
Wavelength
Amino acids in majority of proteins?
Tryptophan, tyrosine and phenylalanine
How do the amino acids in the proteins affect them?
Give absorption maximum of 280nm
What gives absorption peak at 220nm?
Peptide bonds
Absorption peak of nucleic acids and what causes it?
260nm due to pyrimidine and purine bases
Formula for transmission?
T=I/IO
Function of spectrophotometer
To record absorption spectrum, it is commonly used in biochemistry to measure small materials
Parts of spectrophotometer
Light source, Monochromator, sample holder, photodetector, electronic unit, computer and mirrors
How can the spectrophotometer be arranged
Single beam(one curette) and Double beam (2 curettes)
How does light interact with matter
by reflection, absorption, transmission and scattering.
Jablonski schematic?
Electronic, vibrational, rotational transition or all three
How to return from unstable excited state to ground state?
Non radioactive transition and transition with radiation
Note
Flashcard