Dear Colleagues,
I am trying to obtain a geometry optimized structure of C6H5-O-SO3- (singly
deprotonated form of phenyl hydrogen sulfate).
When optimized with HF/6-31G*, the dihedral angle of C-C-O-S was close to 90
degrees but with B3LYP/6-31G* or MP2/6-31G* it was close to 0 degrees.
In addition, the C-C-O-S torsional profile had a minimum at 90 degrees with
HF/6-31G* but at 0 degrees with B3LYP/6-31G* or MP2/6-31G*.
Molecular mechanics minimization (for example, that in PRODRG site) yielded
a structure with 0 degrees.
Is it possible to obtain completely different optimized structures with
different QM methods?
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Received on Fri Oct 02 2009 - 01:00:02 PDT
