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the_density_functional_program [2024/12/16 20:13] – [LibXC functionals] hesselmannthe_density_functional_program [2025/01/09 09:54] (current) – fix layout doll
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 **Important note regarding some functionals from LibXC that also are available in Molpro's internal functional library:** **Important note regarding some functionals from LibXC that also are available in Molpro's internal functional library:**
-A number of functionals which are both available in LibXC and Molpro may give slightly different results (in the micro hartree range for small molecules) due to truncation of significant digits of underlying parameters. And example for this is the PBE functional [[https://doi.org/10.1103/PhysRevLett.77.3865]] in which case the implementation in Molpro uses parameters taken only from the PBE paper some of which are truncated compared to the original source, see references in the PBE paper. Compared to this, LibXC uses a more accurate representation of the parameters in terms of significant digits, resulting to differences in the micro hartree range. Such differences are unlikely to have any effect on energy differences, such as reaction or atomisation energies, but should be kept in mind when comparing total energies calculated with the Molpro and LibXC functionals, respectively.+A number of functionals which are both available in LibXC and Molpro may give slightly different results in total energies (in the micro hartree range for small molecules) due to truncation of significant digits of underlying parameters. An example for this is the PBE functional [[https://doi.org/10.1103/PhysRevLett.77.3865]] in which case the implementation in Molpro uses parameters taken only from the PBE paper some of which are truncated compared to the original source, see references in the PBE paper. Compared to this, LibXC uses a more accurate representation of the parameters in terms of significant digits, resulting to differences in the micro hartree range. Such differences are unlikely to have any effect on energy differences, such as reaction or atomisation energies, but should be kept in mind when comparing total energies calculated with the Molpro and LibXC functionals, respectively.
  
 Functionals known to yield slighty different results according to this: Functionals known to yield slighty different results according to this:
- Molpro      LibXC + 
- PBEX        GGA_X_PBE +^ Molpro ^ LibXC ^ 
- PBEXREV     GGA_X_PBE_R +| PBEX    | GGA_X_PBE | 
- PBEC        GGA_C_PBE +| PBEXREV  | GGA_X_PBE_R |  
- PBESOLC     GGA_C_PBE_SOL +| PBEC     | GGA_C_PBE | 
- PW91C       GGA_C_PW91 +| PBESOLC  | GGA_C_PBE_SOL | 
- HCTH93      GGA_XC_HCTH_93 +| PW91C    | GGA_C_PW91 | 
- HCTH120     GGA_XC_HCTH_120 +| HCTH93   | GGA_XC_HCTH_93 | 
- M06LX       MGGA_X_M06_L +| HCTH120  | GGA_XC_HCTH_120 | 
- B95         MGGA_C_BC95 +| M06LX    | MGGA_X_M06_L | 
- TPSSC       MGGA_C_TPSS +| B95      | MGGA_C_BC95 | 
- M06C        MGGA_C_M06 +| TPSSC    | MGGA_C_TPSS | 
- M06HFC      MGGA_C_M06_HF +| M06C     | MGGA_C_M06 | 
- M062XC      MGGA_C_M06_2X +| M06HFC   | MGGA_C_M06_HF | 
- M06LC       MGGA_C_M06_L +| M062XC   | MGGA_C_M06_2X | 
- M05C        MGGA_C_M05 +| M06LC    | MGGA_C_M06_L | 
- M052XC      MGGA_C_M05_2X +| M05C     | MGGA_C_M05 | 
- M06X        HYB_MGGA_X_M06 +| M052XC   | MGGA_C_M05_2X | 
- M062XX      HYB_MGGA_X_M06_2X+| M06X     | HYB_MGGA_X_M06 | 
 +| M062XX   | HYB_MGGA_X_M06_2X |
  
 ==== Implementing new functionals ==== ==== Implementing new functionals ====
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 The total energy will then be calculated as $$E_{\text{DFT-D2}}=E_{\text{DFT}}+E_{\text{disp}}(\mbox{D2})$$ if $x=d2$ (see Ref. [2]), The total energy will then be calculated as $$E_{\text{DFT-D2}}=E_{\text{DFT}}+E_{\text{disp}}(\mbox{D2})$$ if $x=d2$ (see Ref. [2]),
-$$E_{\text{DFT-D3}}=E_{\text{DFT}}+E_{\text{disp}}(\mbox{D3})$$ if $x=d3$ (see Ref. [3]), and $$E_{\text{DFT-D4}}=E_{\text{DFT}}+E_{\text{disp}}(\mbox{D4})$$ if $x=d4$ (see Ref. [4]).+$$E_{\text{DFT-D3}}=E_{\text{DFT}}+E_{\text{disp}}(\mbox{D3})$$ if $x=d3$ (see Ref. [3]), and 
 +$$E_{\text{DFT-D4}}=E_{\text{DFT}}+E_{\text{disp}}(\mbox{D4})$$ if $x=d4$ (see Ref. [4]).
  
 Currently the default dispersion correction added to the DFT energy is the D4 dispersion correction developed by Grimme //et al.//, see Ref. [4].  Currently the default dispersion correction added to the DFT energy is the D4 dispersion correction developed by Grimme //et al.//, see Ref. [4].