Some questions

[Matt W]

Hi,

On Tuesday, September 20, 2016 at 9:02:20 AM UTC+1, Chris K. Lee wrote:
>
> Hello everyone
>
> I'm trying to run DFT with some molecules.
> The Final goal is to get the informations of the absorption and 
> fluorescence spectrum.
>
> 1.
> For the single molecule, I run it with the poisson solver.
> The molecule has partially periodic sturucture such as grapnehe nano flake.
> Is there any better options or metheods to calculate that kind of 
> molucules?
>
>
There are several Poisson solvers. The 2D Wavelet solver might be helpful 
for you. 
 

> 2.
> Some papers using the CP2K package are handling the Quantum Dots.
> I can arrange each atom's positions in cartesian coordinate.
> But I don't think they calculate in that way.
> How can I run the CP2K package with spherical molecule in nano scale?
>
> Not quite sure what you are asking here. CP2, to my knowledge, always runs 
in cartesian coords, and can be either 0D, 2D or 3D periodic.
 

> 3.
> When I run the TDDFPT, I can get some numbers. But I don't know what it 
> means.
> ------------------------------------------------------------
>   excited state :   1            2.291698
>
>                  48 ->   49             0.995        0.990
>                  47 ->   49             0.099        1.000
> ------------------------------------------------------------
> From here, what does the 1st / 2nd column after the orbital number means?
>
> My group is working on a new implementation of the TDDFPT code, so there 
are two versions available in the latest code. But this bit is the same - 
you get the transition energy (2.29 eV here) then what makes up the 
transition - here it is mainly from the 48th MO to the 49th MO (99%) the 
first column gives the coefficient of the occupied->lumo in the expansion 
of the excited state and the second column (0.99,0 1.000) give the sum of 
the square of the coefficients. 
 

> 4.
> I searched this forum with absorption spectrum, and real time propagation 
> time dependent DFT is the key.
> Is there any test input files in the cp2k package?
>
> Can I get some informations of the fluorescence with CP2K package?
>


There is a recent paper from VandeVondele's group on the real time 
propagation (http://pubs.acs.org/doi/abs/10.1021/acs.jctc.6b00398), some 
test cases in the regtest directories, and a couple of examples here 
(https://www.cp2k.org/exercises:2016_summer_school:excited), which I mean 
to update when I get time. The real time propagation is a different 
approach from the TDDFPT. Which is best for you depends on what you want to 
get out of the calculations.

HTH,

Matt 
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