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kohn-sham_random-phase_approximation [2025/07/30 22:05] – [RPAX2 program] hesselmannkohn-sham_random-phase_approximation [2025/07/30 22:26] (current) – [Kohn-Sham random-phase approximation] hesselmann
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 ====== Kohn-Sham random-phase approximation ====== ====== Kohn-Sham random-phase approximation ======
  
 +This chapter describes three different programs that are related to Kohn-Sham based RPA correlation methods. The first one is the density fitting RPA program of Heßelmann et al. described in section [[Kohn-Sham random-phase approximation#Density fitting RPA programs|Density fitting RPA programs]]. The second one is the ''RPATDDFT'' program by Toulouse et al., see section  [[Kohn-Sham random-phase approximation#Random-phase approximation (RPATDDFT) program|Random-phase approximation (RPATDDFT) program]]. And finally section [[Kohn-Sham random-phase approximation#Self consistent RPA programs|Self consistent RPA programs]] presents a set of programs which can be used to perform self consistent EXX and RPA calculations developed by Trushkin and Görling.
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 +All of the different codes are capable to perform standard RPA correlation energy calculations, but have distinct features which separate them from each other. More details about each program's capabilities can be found in the respective subsections.
 ===== Density fitting RPA programs ===== ===== Density fitting RPA programs =====
  
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 Spin-unrestricted calculations can be done using the **URPAX2** program. In this case the orbitals from a preceeding unrestricted Kohn-Sham calculation have to be passed to the program (via the ''ORB'' key). Spin-unrestricted calculations can be done using the **URPAX2** program. In this case the orbitals from a preceeding unrestricted Kohn-Sham calculation have to be passed to the program (via the ''ORB'' key).
  
-===== ACFDT program =====+==== ACFDT program ====
  
 The ACFDT (adiabatic connection fluctuation-dissipation theorem) method is an alternative approach to derive the RPA. If used in conjunction with local adiabatic exchange-correlation kernels, the method can also describe electron-electron interaction contributions beyond the RPA. Currently, the ALDA xc-kernel can be used in the program (ACFDT(ALDA) method), see also Ref. [4]. The **ACFDT** program has the following options: The ACFDT (adiabatic connection fluctuation-dissipation theorem) method is an alternative approach to derive the RPA. If used in conjunction with local adiabatic exchange-correlation kernels, the method can also describe electron-electron interaction contributions beyond the RPA. Currently, the ALDA xc-kernel can be used in the program (ACFDT(ALDA) method), see also Ref. [4]. The **ACFDT** program has the following options:
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-===== RIRPA program =====+===== Self consistent RPA programs ===== 
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 +==== RIRPA program ====
  
 The RIRPA and URIRPA programs allow non-self-consistent spin-restricted and spin-unrestricted resolution of identity (RI) random phase approximation (RPA) [1-3] and σ-functional [4-6] calculations. These methods should be used in conjunction with conventional Kohn-Sham (KS) density functional theory (DFT) calculations, i.e. data from a preceding KS DFT calculation should be provided. Conventional KS DFT means calculations with LDA, GGA and hybrid exchange-correlation functionals. The RIRPA and URIRPA programs allow non-self-consistent spin-restricted and spin-unrestricted resolution of identity (RI) random phase approximation (RPA) [1-3] and σ-functional [4-6] calculations. These methods should be used in conjunction with conventional Kohn-Sham (KS) density functional theory (DFT) calculations, i.e. data from a preceding KS DFT calculation should be provided. Conventional KS DFT means calculations with LDA, GGA and hybrid exchange-correlation functionals.
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   * **verb** determines the level of verbosity in the output file, integer values of 0, 1, 3 provide different levels of verbosity (default ’0’)   * **verb** determines the level of verbosity in the output file, integer values of 0, 1, 3 provide different levels of verbosity (default ’0’)
  
-===== SCEXX program =====+==== SCEXX program ====
 The ''SCEXX'' and ''USCEXX'' programs allow self-consistent exact-exchange calculations for closed-shell and open-shell systems. The ''SCEXX'' and ''USCEXX'' programs allow self-consistent exact-exchange calculations for closed-shell and open-shell systems.
  
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 {{:uscexx_bef.png?500|}} {{:uscexx_bef.png?500|}}
  
-===== SCRPA program =====+==== SCRPA program ====
 The ''SCRPA'' and ''USCRPA'' programs allow spin-restricted and spin-unrestricted self-consistent random phase approximation calculations. The ''SCRPA'' and ''USCRPA'' programs allow spin-restricted and spin-unrestricted self-consistent random phase approximation calculations.