How can I calculate the dispersion energy using Gaussian 09? Where is it printed in the output file when using wb97xd/cc-pvdz sp
? If it isn't printed by default, what flags can be used to turn printing on?
The value of the empirical dispersion correction is printed when the print level is turned up using #p
in the route line. For any method that contains an empirical dispersion correction, search for R6Disp
or Dispersion energy
, where other parts of the line will vary depending on the type of correction (-D2, -D3, or -D3(BJ)):
R6Disp: Grimme-D2 Dispersion energy= -0.0174233223 Hartrees.
This line is not printed with #
or #n
at the start of the route section.
For wavefunction methods that include dispersion via electron correlation, the dispersion contribution is non-separable. For a method like B2PLYP-D3, the printed "Dispersion energy" is the empirical correction, not the MP2 contribution!
-
1$\begingroup$ This is very good to know and I have to admit I did not know about it. It is one of the neverending shortcomings of the Gaussian manual. $\endgroup$ – Martin - マーチン♦ Jan 19 '17 at 9:03
EmpiricalDispersion=...
if it is parameterized. If not, you can specify the parameters via the command line. See the manual for detail. The omegaB97XD DFA already contains the dispersion; it is parametrized that way. You will not be able to find a value for the dispersion correction. $\endgroup$ – Martin - マーチン♦ Dec 22 '16 at 11:49