Dear QChem community,
I am having problems using the def2-TZVP basis set with iodine atom. Following the manual, beyond Rb atom the keyword “ECP def2-ecp” must be used (page 762 https://manual.q-chem.com/latest/qchem_manual.pdf): example 8.7 shows how to use it (8.12 Built-In ECPs‣ Chapter 8 Basis Sets and Effective Core Potentials ‣ Q-Chem 5.3 User’s Manual). However, when I use it in a simple HF calculation:
"
$molecule
0 1
H 0.0 0.0 0.0
I 0.0 0.0 1.5
$end
$rem
METHOD HF
BASIS DEF2-TZVP
ECP def2-ecp
$end
"
I obtain that the number of electrons is incorrect (it should be 27 alpha 27 beta electrons):
"
Molecular Point Group Cv NOp =**
Largest Abelian Subgroup C2v NOp = 1
Nuclear Repulsion Energy = 8.81962018 hartrees
There are 13 alpha and 13 beta electrons
Requested basis set is def2-TZVP
There are 20 shells and 56 basis functions
"
Do you know what is happening here? Thank you very much in advance for your help.