Hi everyone,
I'm calculating RI-MP2 energies for a certain adduct system.
This system exists of two fragments and the second fragment can contain Cl, Br or I.
I am calculating MP2 energies using the
$ricc2
geoopt model=mp2
setup and using default values for $freeze, $cbas as chosen by default by define.
I did the normal MP2 singlepoint without problems with
dscf > outputfile1
ricc2 > outputfile2
and then the BSSE correction in a separate folder (but with the same input files) by
jobbsse -level cc2 -ri
Everything runs fine for Cl- and Br-containing systems, and I get a BSSE correction of about 2.5 kJ/mol (basis set is def2-TZVPP).
For iodine, I get strange results.
My RI-MP2 (no bsse correction) energy is
MP2 energy = -776.363....
but in bsse_out I get
CP-corrected total energy -248.054...
Obviously this makes no sense. I have also noted that the "CP-Correction to total energy" is 528.30... hartree, so by far too large.
I'm using TM6.0 and standard settings for the basis sets (so my def2-TZVPP for Iodine has an ECP).
My $freeze reads "implicit core= 15 virt = 0".
I am guessing that the $freeze settings are wrong, so could you tell me what a recommendable setting would be, using ECP?
Or is there a general problem with jobbsse and ECPs?
Thanks a lot in advance!