In Section 6.2 I used the symbol as an abbreviation for the constant . This constant is ordinarily measured by microwave spectroscopy: bombarding' the molecule with microwaves and looking at what frequencies are absorbed.

Step 1</p>

To calculate the microwave frequency of the radiation when transition takes place from j=0 level to j=1 for a CO molecule.

The energy required to excite the CO molecule form j=0 level to j=1 level is

Where h is plank’s constant and f is the frequency.

The energy required to excite the CO molecule from j=0 level to j=1 level is equal to difference between energies of j=1 and j=0 states.

Here E1 is the energy of the CO molecule for j=1 state and E0 is the energy of the CO molecule for j=0 level.

Substitue for in the equation

And solve for f

1.5091

Step 2</p>

Here E1 is the energy of the CO molecule for j=1 state and E0 is the energy of the CO molecule for j=2 level.

Substitue for in the equation

And solve for f

-1.5091

Step 3</p>

Now

Calculating reduced mass

To find moment of inertia of CO molecule.