What’s the difference between TD-DFT and TD-DFPT?

[mshakiba.k...@gmail.com]

Hello everyone,

Can you please explain the difference between TD-DFT and TD-DFPT? Why CP2K just doesn't use TD-DFT? and where can I read more about this method, the TD-DFPT?

Thanks in advance.

[Matt W]

TD-DFT is the generalisation of DFT to a time dependent problem and can be used in various ways. TD-DFPT is a particular method using Perturbation Theory to calculate properties from the general TD-DFT theory. You should get references to the papers concerned if you run CP2K ' Time-dependent density functional response theory for molecules, ME Casida Recent Advances In Density Functional Methods: (Part I), 155-192' is perhaps one of the best known papers setting out the approach (for molecular systems).

Matt

[mshakiba.k...@gmail.com]

Dear Professor Watkins,

Thank you so much for your response to this question.