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howto:cdft [2018/07/24 05:38] – Update to CP2K 6.1 nholmberhowto:cdft [2018/11/01 08:57] – [CDFT in summary] nholmber
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 A more exhaustive list of potential applications has been presented in this [[doi>10.1021/cr200148b | review article]]. A more exhaustive list of potential applications has been presented in this [[doi>10.1021/cr200148b | review article]].
  
-The charge and spin localized states are created by enforcing electron and spin density localization within atom centered regions of space. The relevant theory has been derived by Wu and Van Voorhis in a series of key papers: [[doi>10.1103/PhysRevA.72.024502 | paper 1]],  [[doi>10.1063/1.2360263 | paper 2]],  [[doi>10.1063/1.2360263 | paper 3]]. Further useful references can be found in the aforementioned review article. The CDFT implementation of CP2K has been throughly described in this [[doi>10.1021/acs.jctc.6b01085 | publication]].+The charge and spin localized states are created by enforcing electron and spin density localization within atom centered regions of space. The relevant theory has been derived by Wu and Van Voorhis in a series of key papers: [[doi>10.1103/PhysRevA.72.024502 | paper 1]],  [[doi>10.1063/1.2360263 | paper 2]],  [[doi>10.1063/1.2360263 | paper 3]]. Further useful references can be found in the aforementioned review article. The CDFT implementation of CP2K has been throughly described in these two papers: [[doi>10.1021/acs.jctc.6b01085 | paper 1]] and [[doi>10.1063/1.5038959 | paper 2]].
  
-In this tutorial, only the main results needed to understand what is happening during a CDFT simulation will be summarized. The charge/spin localized states can be generated by augmenting the Kohn-Sham energy functional, $E_\mathrm{KS}$, by additional constraint potentials+In this tutorial, only the main theoretical aspects needed to understand what is happening during a CDFT simulation will be summarized. The charge/spin localized states can be generated by augmenting the Kohn-Sham energy functional, $E_\mathrm{KS}$, by additional constraint potentials
  
 \begin{equation} \begin{equation}
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 \end{equation} \end{equation}
    
-where $c_j$ are atomic coefficients which determine how each atom is included in the constraint (more on this later), $P_j$ is the so-called cell function which determines the volume occupied by atom $j$ according to some population analysis method, and $\mathcal{N}$ is the set of all atoms in a system. Currently, only the Becke partitioning scheme is fully supported in CP2K, which will be elaborated in the following section. Different types of constraints can be constructed by modifying the weight function according to the following conventions +where $c_j$ are atomic coefficients which determine how each atom is included in the constraint (more on this later), $P_j$ is the so-called cell function which determines the volume occupied by atom $j$ according to some population analysis method, and $\mathcal{N}$ is the set of all atoms in a system. Different types of constraints can be constructed by modifying the weight function according to the following conventions 
   * charge density constraint ($\rho^\uparrow + \rho^\downarrow$): $w^\uparrow = w^\downarrow = w$   * charge density constraint ($\rho^\uparrow + \rho^\downarrow$): $w^\uparrow = w^\downarrow = w$
   * magnetization density constraint ($\rho^\uparrow - \rho^\downarrow$): $w^\uparrow = -w^\downarrow = w$   * magnetization density constraint ($\rho^\uparrow - \rho^\downarrow$): $w^\uparrow = -w^\downarrow = w$
   * spin specific constraint ($\rho^{\uparrow/\downarrow}$): $w^{\uparrow/\downarrow} = w, w^{\downarrow/\uparrow} = 0$   * spin specific constraint ($\rho^{\uparrow/\downarrow}$): $w^{\uparrow/\downarrow} = w, w^{\downarrow/\uparrow} = 0$
  
-When CDFT is used in a molecular dynamics or a geometry optimization simulation, additional force terms arising from the constraints are calculated+The Becke and Hirshfeld space partitioning schemes can be used as constraint weight functions in CP2K. The main differences between these two constraints will be explained in a subsequent section. Please note that Becke constraints have been tested much more extensively.  
 + 
 +When CDFT is used in a molecular dynamics or a geometry optimization simulation, additional force terms arising from the constraints are calculated (currently only implemented for Becke constraints)
  
 \begin{equation} \begin{equation}
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 ===== Using the CDFT module ===== ===== Using the CDFT module =====
  
-The input sections [[inp>FORCE_EVAL/DFT/QS/CDFT]] and [[inp>FORCE_EVAL/DFT/QS/BECKE_CONSTRAINT]] are used for setting up a CDFT simulation. A brief description of these sections will be given in the next two subsections. Subsequently, various aspects of running CDFT simulations will be explored through example calculations.+The input section [[inp>FORCE_EVAL/DFT/QS/CDFT]] is used to set up a CDFT simulation. A brief description of this input section will be given in the next two subsections. Subsequently, various aspects of running CDFT simulations will be explored through example calculations.
  
 ==== Defining CDFT SCF parameters  ===== ==== Defining CDFT SCF parameters  =====
howto/cdft.txt · Last modified: 2024/01/03 13:20 by oschuett