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Messages - johannes.mckay

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1
Simulations / Re: Cartesian interaction matrix into spherical tensor
« on: July 26, 2012, 08:19:46 PM »
Hi Malcolm

Cheers for the notebook, I am just looking at it just now. I will go back and revise and check some things based on this as I think I might have been going down the wrong path with SphericalTensorOperatorBasis in that case.

I will post back with notable successes or failures!

Cheers,
Johannes

2
Code: [Select]
intmat = {
     {-1.1, 0., 0.},
     {0., -1.3, 0.},
     {0., 0., 2.2}
    } ;
intmat // MatrixForm
operatorDint = opI["S1"].intmat.opI["S2"]
ExpressOperator[operatorDint, SphericalTensorOperatorBasis[]]
Fails as the zeros are Real and not integer. A workaround is to use chop but this wasn't too obvious from the error message which is returned on entering the code above.
Although an easier work around is obviously to specify
Code: [Select]
intmat = {
     {-1.1, 0, 0},
     {0, -1.3, 0},
     {0, 0, 2.2}
    } ;
but if I was to multiply this by a real constant then mathematica would make the zero elements real again making chop necessary again.

Hopefully this makes some sense. Cheers,
Johannes

3
Simulations / Re: Cartesian interaction matrix into spherical tensor
« on: July 02, 2012, 04:53:42 PM »
Hi Jyrki, Having a quick scan of ?SphericalTensorOperatorBasis I think this is the generating function that I am missing. I will give this a go tonight and see how I get on. Thanks for the quick reply.

Cheers,
Johannes

4
Simulations / Cartesian interaction matrix into spherical tensor
« on: July 02, 2012, 09:28:47 AM »
Thanks for any help to this question(s)!

I am having a bit of trouble translating a cartesian interaction matrix into a spherical tensor, I have managed to do this by hand following the guide handed out by Ilya and using the tables of coefficients, but doing it in SpinDynamica leaves me a little bit lost. Are there any functions particularly suited to this operation, I didn't find anything in the usage examples but I might have missed them?

Cheers,
Johannes

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