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grimme-lab / xtb

Semiempirical Extended Tight-Binding Program Package
https://xtb-docs.readthedocs.io/
GNU Lesser General Public License v3.0
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ALPB solvation energy printout #617

Open chburger opened 2 years ago

chburger commented 2 years ago

I wanted to calculate the solvation energy of water in water using the implicit solvation model with xtb coord --alpb water using xtb version 6.4.1. The calculated solvation energy differs from the values on the documentation page and the Born term is not printed at all. Any advice? own calculation:

:::::::::::::::::::::::::::::::::::::::::::::::::::::
::                     SUMMARY                     ::
:::::::::::::::::::::::::::::::::::::::::::::::::::::
:: total energy               -5.080052453799 Eh   ::
:: total w/o Gsasa/hb         -5.072629830168 Eh   ::
:: gradient norm               0.004391355361 Eh/α ::
:: HOMO-LUMO gap              14.784541887474 eV   ::
::.................................................::
:: SCC energy                 -5.113963912352 Eh   ::
:: -> isotropic ES             0.042951967946 Eh   ::
:: -> anisotropic ES          -0.000414697277 Eh   ::
:: -> anisotropic XC          -0.000390138125 Eh   ::
:: -> dispersion              -0.000131341861 Eh   ::
:: -> Gsolv                   -0.011759733450 Eh   ::
::    -> Gborn                -0.004337109820 Eh   ::
::    -> Gsasa                 0.000220003644 Eh   ::
::    -> Ghb                  -0.009500070401 Eh   ::
::    -> Gshift                0.001857443127 Eh   ::
:: repulsion energy            0.033911458523 Eh   ::
:: add. restraining            0.000000000000 Eh   ::
:::::::::::::::::::::::::::::::::::::::::::::::::::::

from the documentation page:

https://xtb-docs.readthedocs.io/en/latest/gbsa.html

:::::::::::::::::::::::::::::::::::::::::::::::::::::
::                     SUMMARY                     ::
:::::::::::::::::::::::::::::::::::::::::::::::::::::
:: total energy               -5.080052453799 Eh   ::
:: total w/o Gsasa/hb         -5.072629830168 Eh   ::
:: gradient norm               0.004391355361 Eh/α ::
:: HOMO-LUMO gap              14.784541887474 eV   ::
::.................................................::
:: SCC energy                 -5.113963912352 Eh   ::
:: -> isotropic ES             0.042951967946 Eh   ::
:: -> anisotropic ES          -0.000414697277 Eh   ::
:: -> anisotropic XC          -0.000390138125 Eh   ::
:: -> dispersion              -0.000131341861 Eh   ::
:: -> Gsolv                   -0.011759733450 Eh   ::
::    -> Gborn                -0.004337109820 Eh   ::
::    -> Gsasa                 0.000220003644 Eh   ::
::    -> Ghb                  -0.009500070401 Eh   ::
::    -> Gshift                0.001857443127 Eh   ::
:: repulsion energy            0.033911458523 Eh   ::
:: add. restraining            0.000000000000 Eh   ::
:::::::::::::::::::::::::::::::::::::::::::::::::::::
         :: SCC energy                -5.119271225600 Eh    ::
         :: -> isotropic ES            0.049109362930 Eh    ::
         :: -> anisotropic ES         -0.001190505920 Eh    ::
         :: -> anisotropic XC         -0.000287434439 Eh    ::
         :: -> dispersion             -0.000127118435 Eh    ::
         :: -> Gsolv                  -0.019199729456 Eh    ::
         ::    -> Gelec               -0.007356343170 Eh    ::
         ::    -> Gsasa                0.001917640374 Eh    ::
         ::    -> Ghb                 -0.014841786358 Eh    ::
         ::    -> Gshift               0.001080759698 Eh    ::
         :: repulsion energy           0.034254423478 Eh    ::
         :: add. restraining           0.000000000000 Eh    ::
         :: total charge               0.000000000000 e     ::
         :::::::::::::::::::::::::::::::::::::::::::::::::::::
awvwgk commented 2 years ago

We renamed the contribution from Gborn to Gelec in the output to also account for non-Born based solvation models like PCM.

moabe84 commented 8 months ago

Hi, I have a question regarding the changes to the ALPB solvation energy printout. The experimental solavtion free energy of water molecule in water solvent is -6.3 kcal/mol (-0.0100 Eh). The Gsolv value calculated by xTB is -0.019 Eh, while it was -0.011 Eh before, which is much closer to the experimental value. I wonder if I'm missing anything here to interpret the results. Any comments or suggestions are greatly appreciated. Thanks.