Full set of Notes with Fill-Ins - San Jose State University

Chem 155 Unit 15 264 of 316Radiation interacts with molecules by inducing adipole moment.The induced dipole ‘m’ is proportional to thepolarizability, α.m( )α⋅Eα⋅E 0 ⋅cos 2⋅π⋅ν ex ⋅tBut the polarizability is itself oscillating!dαα α 0 dr r r dα+ ( − e)α 0 +dr⋅( ( ))r A ⋅cos 2⋅π⋅ν vib ⋅tSo the induced dipole moment is oscillating in a morecomplex way:m E 0 ⋅α 0( )⎛⎝( )dα⋅cos 2⋅π⋅ν ex ⋅t⋅⎜α 0 +dr ⋅rA⋅cos 2⋅π⋅ ν vib⋅tThe dynamic induced dipole that gives rise to Raman scattering:⎞⎟⎠Incident E-fieldOscillatingpolarizabilityAmplitudemodulation ininduced dipolePage 264 of 316