Sunday, May 25, 2008

PreExam MerryGoRound O Questions 2

Fire away, again.

14 comments:

Ian said...

How exactly do you determine +/- for atomic term symbols, because apparently i'm just shooting for a 50/50 chance of getting it right at the moment

Ian said...

And by atomic term symbol, i mean Molecular.

rod said...

You will need to come see me for that explanation. It is all about shapes of orbitals

Ashlee said...

For the molecular selection rules, what's the deal with the plus/minus when you're trying to find the possible transitions from an odd LAMBDA? Odd ones don't have the plus/minus designation, so can it transition to both plus and minus even LAMBDAs?

rod said...

Yes. In other words, odd Λ states have no restriction in their transitions to +/-.

Ashlee said...

How does the LCAO-MO approach change for different bond types? Is it only good for sigmas? Do we have to use the HMO theory for pi-systems?

rod said...

No, LCAO is used pretty much for all molecular orbitals, from sigma all the way up through pi, delta and phi. HMO theory is built on top of LCAO.

Ashlee said...

So how does it change with the different orbitals? For multiple you just add more terms but how do they change for pi+?

rod said...

I'm sorry, I don't understand, your question is too vague.

Ashlee said...

The method shown to us is specific for sigma orbitals. Certainly the orbital wavefunctions would be different for pi orbitals. But with this method we don't even know what these wavefunctions are and they're eventually dwindled down to coulomb and exchange integrals. How can we distinguish a sigma from a pi?
Does anyone else know what I'm getting at and can ask a better question?

Anonymous said...

I seemed to have misplaced my final exam topic sheet and was wondering if you could post it on the website.

Anonymous said...

Is the quantization of rotation and vibration just m(sub)l?

rod said...

That question is fairly vague, since quantization is a process and quantum number is a mathematical construct.

That said, I'll answer the question I think you were trying to ask:

ml is associated with quantization of rotation and has nothing to do with vibration.

Anonymous said...

What are plausibility arguments in regards to psi?