# RE: bsse and second derivatives in G98

*From*: Joao Brandao <jbrandao { *at * } ualg.pt>
*Subject*: RE: bsse and second derivatives in G98
*Date*: Mon, 31 Jan 2000 13:03:05 -0000

I think it is a mathematical problem, not a physical one.
Being the BSSE a correction done subtracting different energies and the
force field a second derivative of the energy, it should be OK to subtract
the different force fields to account for a force-field BSSE corrected.
Instead of compute a BSSE corrected energy for each configuration and
numerically compute the second derivatives of the potential energy surfaces,
we can compute numerically the second derivatives for each term and BSSE
correct those second derivatives. If the steps in the numeric procedure are
the same the results should be the same.
If we calculate analytically the derivatives, better.
Joao Brandao
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After I sent this message, I notice the one from Artem Masunov that, I
think, explains correctly the problem.
Joao Brandao