Physics for Information Science: Unit IV: Optical Properties of Materials
Colour Centres of Optical Properties of Materials
Pure ionic crystals like NaCl, KCI etc. are transparent when visible light is passed through them.
COLOUR
CENTRES
Pure
ionic crystals like NaCl, KCI etc. are transparent when visible light is passed
through them. However, these crystals may be made to appear coloured by any one
of the following ways.
(i)
Adding impurities.
(ii)
Adding metal ions.
(iii)
By bombarding the crystals with X-ray, y-ray, neutron (or) electron.
(iv)
Electrolysis.
In
all these methods, vacancies will be created in the crystal. These vacancies,
so called defect centres will capture the electrons (or) holes and are capable
of absorbing the visible light. Thus the crystal will be coloured.
Colour Centres: Colour centres are the lattice
defects (or) crystal imperfections which absorb the visible light, so that the
crystal is coloured.
Physics for Information Science: Unit IV: Optical Properties of Materials : Tag: : - Colour Centres of Optical Properties of Materials
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PH3256 2nd Semester CSE Dept | 2021 Regulation | 2nd Semester CSE Dept 2021 Regulation