Simulation of rotational spectra of a symmetric top

[luisgml_2000]

Hello fellow physicists,

I have a query about a practical matter. I'm trying to simulate the rotational spectrum of a symmetric top and so far I've been able to produce a stick spectrum of it.

My first problem is that the lines do not exactly match the positions of the peaks but my biggest problem is that I need to simulate the intensities of the rotational lines. I've looked into Kovacs' "Rotational Structure in the spectra of diatomic molecules" as it contains a discussion of the topic but the conclusion of the book is that I need the components of the electronic transition moment; in the end, I need th wavefunction of my molecule and I don't know it. Something tells me that this is the wrong way to go.

I'm aware of programs like PGopher that could do the job but I need to do this thing myself for the sake of my project.

If you could help me out in this undertaking with a piece of advice or a useful reference I'd really appreciate it.

Thanks.

 

[DrDu]

Of course you need the moment to calculate the absolute height of the lines but I think by using the Wigner Eckart theorem it should be possible to get all the relative intensities.