Dear Users and Developers of TM,
I recently faced a disagreement of CC2 and MP2 in predicting
the most thermodynamically favorable conformation of an organic
molecule. More exactly there are two isomers which are very close
in energy (the energy difference is less than 1 kcal/mol). Nonetheless
I expected that CC2 and MP2 should agree in predicting the
lowest energy isomer. But they do not!
I checked these isomers with DFT (B3LYP and B97-D) and the results
are in agreement with CC2. So I am somewhat baffled why pure ab
initio methods give different results. Any opinion would be greatly appreciated!
Best,
Evgeniy
