Characteristics of Raman Polarizability (5) Flashcards
What is a dipole vector?
dipole moment direction and magnitude; charge of photon line to charge electron
What is a tensor?
polarizability; due to unequal polarizability of electron cloud
How can raman polarizability be defined in terms of tensor character
3x3 matrix describing liner relationship between vectors
What are the components of the polarizability tensor αij?
9 combinations of α xyz
Polarizability ellipsoid
since δ is symmetric, defined using 6 components
how do you define the condition for raman activity in relation to the components of the polarizability tensor αij?
ellipsoid changes size, shape, orientation because of molecular rotation/vibration results in Raman spectrum; any change in any of the 6 αij results in Raman spectrum
Why are depolarization ratios important in Raman spectroscopy?
useful in determining molecular structure and correlating raman lines with modes of vibration
What is a completely polarized Raman vibration?
ratio = 0
What is a polarized Raman vibration?
ratio less than .75
What types of vibrations give small values for their depolarization ratios?
total symmetry
What is a depolarized Raman vibration?
ratio greater than or equal to .75
What types of vibrations are depolarized?
nonsymmetrical
What is the rule of mutual exclusion?
relates the observation of molecular vibrations to molecular symmetry
When does the rule of mutual exclusion apply?
when there is a center of symmetry
