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howto:cdft [2018/11/02 12:50] – [Selected examples] nholmberhowto:cdft [2018/11/02 12:51] – [Example: Configuration interaction calculations with CDFT (CDFT-CI): The case of $\mathrm{H}_2^+$] nholmber
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 We can use CDFT states as the basis of a configuration interaction (CI) simulation to correct for SIE in this system. As the figure above shows, CDFT-CI using the PBE functional is able to reproduce the exact dissociation profile. You can read up on the theory behind CDFT-CI simulations from the references given at the start of this tutorial. Very briefly, CDFT-CI simulations involve representing the system's wavefunction as a linear combination of multiple CDFT states where the charge/spin density is constrained differently in different states. The CI expansion coefficients and energies are then obtained by solving a generalized eigenvalue equation where the effective Hamiltonian matrix describes how the CDFT states interact with each other.  We can use CDFT states as the basis of a configuration interaction (CI) simulation to correct for SIE in this system. As the figure above shows, CDFT-CI using the PBE functional is able to reproduce the exact dissociation profile. You can read up on the theory behind CDFT-CI simulations from the references given at the start of this tutorial. Very briefly, CDFT-CI simulations involve representing the system's wavefunction as a linear combination of multiple CDFT states where the charge/spin density is constrained differently in different states. The CI expansion coefficients and energies are then obtained by solving a generalized eigenvalue equation where the effective Hamiltonian matrix describes how the CDFT states interact with each other. 
  
-In this tutorial, you will reproduce the DFT and CDFT results from the figure above. You can find the input files here. The reference data used to plot Figure 4 are also included in the zip-folder. Please note that the reference results were obtained with a larger basis set and planewave cutoff as well as tighter convergence criteria than the settings you will be using in this tutorial.+In this tutorial, you will reproduce the DFT and CDFT results from the figure above. You can find the input files {{:howto:cdft-tutorial-h2.zip|here}}. The reference data used to plot Figure 4 are also included in the zip-folder. Please note that the reference results were obtained with a larger basis set and planewave cutoff as well as tighter convergence criteria than the settings you will be using in this tutorial.
  
   - Start by examining the simulation script ''energy.bash''. This tutorial involves a rather large number of simulations so running them will take a while. You can use the flag ''-x'' to separately run the different types of simulations (DFT, CDFT, CDFT-CI) needed in this tutorial.   - Start by examining the simulation script ''energy.bash''. This tutorial involves a rather large number of simulations so running them will take a while. You can use the flag ''-x'' to separately run the different types of simulations (DFT, CDFT, CDFT-CI) needed in this tutorial.
howto/cdft.txt · Last modified: 2024/01/03 13:20 by oschuett