Dynamic polarizability of Au+ ion

[André Campos]

Dear all

 I am calculating the dynamic polarizability of gold with dirac. I see a transition around w=0.35 a.u so I define a damping=0.005. But this transition has a very long lifetime, t=3.4 ns and would have correspondingly a damping=10^(-7) but this is too small to put in dirac. Do you think my results make sense? I used damping=0.005. I plot the real and imaginary part of the polarizability wrt frequency in polarizability.jpg and also its fourier transform in poltime.jpg. Does these plots make sense? I do not have experience with this kind of calculations so I am not sure how to interpret these results.

 Thanks a lot

Andre

[Hans Jørgen Aagaard Jensen]

1. Why do you state that damping=10^(-7) is too small, have you tried? I have not been involved in this code, but I just checked in the code and there was no obvious reason 10^(-7) should not work. The appropriate input would be
   .DAMPING
    1.e-7
2. It sounds as if you haven't read the two references on the page with the tutorial for complex response on http://www.diracprogram.org/doc/release-12/tutorials/properties/complex_response.html . Just for the record, these two articles should of course be referenced if complex response results calculated with DIRAC are published.

-- Hans Jørgen.

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[André Campos]

I think the problem was that I was not correctly defining the damping parameter. I was using 0.0000001. I will try with the new way you suggested. Thanks

Andre

[André Campos]

I've tried damping=1.e-7 and got very large polarizabilities around the resonance frequency. Should I use a much larger damping then if though the lifetime is quite large for the transition? 

[bala...@gmail.com]

Dear Dirac experts,

I could see in this thread that the response properties can be calculated at the HF level of theory. 

 I am wondering if the response properties, e.g. dynamic polarizability, can be computed at the CC level of theory for the ground and excited state. 

Thanks in advance!

Regards,

Renu

[Andre Gomes]

Hi,

It is currently possible to calculate static or dynamic polarizabilities at CC level of theory for the ground state using the exacorr module.

Please have a look at the manual (https://diracprogram.org/doc/release-24/manual/wave_function/exacorr.html) for a description and and under the test/exatensor_talsh_ccrsp_lr_* directories in the source code for sample inputs.

There is currently no analytic implementation of excited state dynamic polarizabilities at CC level of theory though.

Best regards,

Andre

To view this discussion visit https://groups.google.com/d/msgid/dirac-users/6d7acf3a-7ffb-4f66-a028-a13ce5d8c1ffn%40googlegroups.com.

[bala...@gmail.com]

Dear Andre,

Thank you very much for the information.

Regards,

Renu