So we've worked out our L.

So, to understand the the, the spectra, what you get in when you absorb

radiation, is you get a transition from, from one energy level to the other.

So we can draw out our energy levels here for

the for the particle in the box, which is light.

So here we have a qualitative energy level guy, and here we have E.

And here we have our different energy levels, for our particle in the box.

So here we have n equals 1, n equals 2, n equals 3, n equals

4 and, and so far on, we could keep going, and now we can know,

let's put them in a, in a different color here, we know the

energies of these from our particle in a box presentation.

So they're h squared over 8 mL squared, for n equals 1.

What you then have, you have 4h squared, all over 8 mL squared for n equals 2.

And then you have 9h squared, all over 8 mL squared, for n equals 3.

Now, so what happens when you irradiate this at the right frequency?

So you have h new radiation frequency

coming in here, is you cause an excitation.

Now let's first of all, we have 4 pi electrons,

so we have to fill these electron energy levels, levels up.

So we can fill them up as so.

So with 4 electrons, and as fill, you

learned again in general chemistry, you put 2

electrons into each, and you have you have

opposite spins for the, for the two electrons.

So that would be your four pi electrons in the, in the butadiene molecule.

Now, when you come along with the appropriate radiation, and you

can match this gap here, n equals 2 to n equals 3,

what you get is you get a transition of this electron

from the n equals two level to the n equals 3 level.

So if we go over here, we again have our, sketch out our energy levels.