Question about charge difference density and transition density!


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Dear all,

I want to calculate the charge difference between excited state S1 and ground state S0,

\rho_{S1}(r) - \rho_{S0}(r)

and transition density between S1 and S0:

\rho_{S1, S0}(r) = \phi^*_{S1}(r) * \phi_{S0}(r)

But I did not find the keyword to do this in NWchem.

Could anybody tell me how to calculate these densities?

Thanks very much in advance.

Forum Regular
Hi Ylniu,

I am not sure whether NWChem supports calculating those quantities. But before I can say for sure I would need to know which code module you are using. Could you let me know, please?

Huub

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Dear Huub,

I use nwdft/lr_tddft to calculate the excited states with TDDFT. I can get the eigenvectors of excited states, which represented the coefficients of the transition density matrix. But to generate the transition density cube is not easy to me.

For Difference density, I do not understand its definition, because I do not understand how to define the total density of excited state. From the eigen-equation of TDDFT. We can get the coefficients of the transition density matrix. But how to generate the total density of the excited state from the transition density?

For the reference: Filipp Furche, On the density matrix based approach to time-dependent density functional response theory, J. Chem. Phys., 2001, Vol. 114, Pages: 5982-5992. Eq(49).

   Thanks for your reply and kind help!

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XDM energy
I am using the lest development version, 07.
When I look at the total energy after convergence I think that this does not include the contribution of the dispersion XDM.
Is that normal and this contribution should be added by hand ?
jean-louis

Forum Vet
Jean-Louis,
please see post
http://nwchemgit.github.io/Special_AWCforum/st/id1361/xdm_and_total_energy.html


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