Classical Raman (5) Flashcards
What is an induced dipole moment?
dipole moment caused by external electric and magnetic fields of laser radiation
How are induced dipole moments mathematically expressed?
µ = α E
What is polarizability
degree of deformation of electron cloud by incident electric field
How is polarizability related to the selection rule for raman activity?
to be raman active vibration must be accompanied by a change in polarizability
What are the three components of the classical electromagnetic field equation for µ?
max value applied electric field, frequency applied radiation, time
How does classical electromagnetic theory describe Rayleigh scattering?
reradiation of induced dipole at incident frequency V0
How does classical electromagnetic theory describe Stokes Raman scattering?
electronic polarizability changes during vibrational displacement, with induced dipole varying as a function of (v0-vv)
How does classical electromagnetic theory describe Anti-Stokes Raman scattering?
electronic polarizability changes during vibrational displacement with induced dipole vary as function (v0+vv)
What is Raman spectroscopy?
An inelastic scattering process involving an induced dipole moment caused by application of external electric field from incident radiation
How does Rayleigh scattering arise?
from the induced polarized dipole moment bc of an oscillating electric dipole of frequency re-radiating electromagnetic field of equal frequency
Raman scattering produced by
induced dipoles oscillating at frequencies of v0 =+/- vv
oscillating of induced dipoles at frequencies v0 +/- vv occurs when
the underlying dipole oscillation is modulated by the higher frequency vibrational oscillations
What is the primary deficiency of classical electromagnetic theory when describing raman scattering?
predicts equal intensities for stokes and anti stokes raman bands
