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--- the_density_functional_program [2024/07/12 08:37] – external edit 127.0.0.1
+++ the_density_functional_program [2025/01/09 09:54] (current) – fix layout doll
@@ Line 965: / Line 965: @@
+**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 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:
+^ Molpro ^ LibXC ^
+| PBEX    | GGA_X_PBE |
+| PBEXREV  | GGA_X_PBE_R |
+| PBEC     | GGA_C_PBE |
+| PBESOLC  | GGA_C_PBE_SOL |
+| PW91C    | GGA_C_PW91 |
+| HCTH93   | GGA_XC_HCTH_93 |
+| HCTH120  | GGA_XC_HCTH_120 |
+| M06LX    | MGGA_X_M06_L |
+| B95      | MGGA_C_BC95 |
+| TPSSC    | MGGA_C_TPSS |
+| M06C     | MGGA_C_M06 |
+| M06HFC   | MGGA_C_M06_HF |
+| M062XC   | MGGA_C_M06_2X |
+| M06LC    | MGGA_C_M06_L |
+| M05C     | MGGA_C_M05 |
+| M052XC   | MGGA_C_M05_2X |
+| M06X     | HYB_MGGA_X_M06 |
+| M062XX   | HYB_MGGA_X_M06_2X |
 ==== Implementing new functionals ====
@@ Line 1289: / Line 1306: @@
 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].