CCL: BSSE correction for transition states
- From: "John Simmie"
- Subject: CCL: BSSE correction for transition states
- Date: Mon, 1 Jul 2019 02:42:32 -0400
Sent to CCL by: "John Simmie" [john.simmie++nuigalway.ie]
The original post was concerned with bimolecular reactants & transition
states and whether corrections are required. AFAIK the conclusion reached by
Lendvay and Mayer [https://doi.org/10.1016/S0009-2614(98)01191-9]:
"We performed a theoretical and numerical analysis of the different
`counterpoise correction' (CP) schemes potentially applicable to correct for the
basis set superposition error (BSSE) in the neighborhood of transition
structures of chemical reactions. The analysis proved that neither of them is
satisfactory: all CP versions result in either discontinuous potential surfaces
or yield different energies for the same species in different reactions.
Standard CP correction is unavoidable and satisfactory when loosely bound pre-
or post-reaction complexes are studied. For transition structures, however,
doing no correction is better than any available CP method."
Has never been countermanded and most if not all practicing kineticists would
apply a counterpoise correction to pre-reaction and post-reaction complexes if
necessary but that's all. Of course swamping with basis functions is also a
good idea if that is feasible for the particular system being studied.
John M. Simmie//School of Chemistry//National Univ. of Ireland, Galway