Dear
CCLers:
The problem of the entropy component in solvent was tackled for
instance in J. Am. Chem. Soc. 2004, 126, 10457 and Organometallics 2006, 25,
3647 by simply deleting the rotational and translational entropy. This extreme
approach can be sometimes more accurate than putting all the free energy
components in the same basket with the solvation. Comparing my simple gaussian
values with the more accurate ones of J. Chem Phys 107, 1997, 1981, convinced me
that for charged molecules in high dielectric solvents it's better to delete the
entropy in gas phase.
For a Ni neutral complex in THF solvent I found that
the accurate values where roughly in the middle between full free energy and
E+ZPE. This compared to experimental values and considering my DFT calculations
accurate enough. Clearly gaussian overestimates the translational and rotational
entropies. It would have been
nice a manual that explains this behaviour. I've heard of programs that correct
this, but still I couldn't find a good manual for them
also.
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx..........Sebastian
Kozuch...........xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx...The Lise
Meitner-Minerva Center....for Computational Quantum
Chemistry....Hebrew University
of Jerusalem.........kozuchs_-_yfaat.ch.huji.ac.il.....http://yfaat.ch.huji.ac.il/kozuch.htmxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx