Roational Spectroscopy Flashcards
What is rotational spectroscopy
The study of how electromagnetic radiation interacts with a molecule to change its rotational energy
In what conditions can a molecule freely rotate
Gas
What is the moment of inertia
Resistance to rotation
What is the equation for moment of inertia
M1r1^2 +m2r2^2
What is rotational energy
Kinetic energy due to rotation
What is the equation for rotational energy
EN= 1/2I angular velocity ^2
How are the energy levels spaced
Closely
In what region are rotational transitions
Microwave
What is a rigid diatomic
A diatomic with fixed bond length
What is Ej = for rigid diatomic
BJ(J+1) where j =0,1,2,3…
What does J do
Quantise energy
What does B do
Links to specific molecule
What is the lowest energy level
0
What does it mean if energy is 0
No rotation occurring
What do the gaps do as energy levels increase
Increase in space
What is the equation for rotational constant B
= h/8pi^2Ic
What is reduced mass
M1m2/m1+m2
What is delta Ej equal to
2B(J+1)
What is the gross selection rule?
Must have a change in dipole on rotation
What is the specific selection rule
Delta j =+-1
How many bands are shown in a spectrum
Many
What determines strength of band
Population
What is population proportional to
(2J + 1) e^(-Ej/KT)
What effect does the molecule not being rigid have
It can stretch
