> My energy differences of 120 and 240 kJ/mole are far too high for > polymorphs (see ?ref [1]). > Am I mistaken to equalize the "total energy" of pwscf-output with the > "lattice energy" (former "structure energy")? > I'm aware of the missing Entropy - but it is told to be negligible > small...
I'm not entirely sure I understand your problem; I just want to remind that total energy periodic system does not have any absolute meaning: only energy differences count. So, with what are you comparing the energy of your crystal? As your reference is in kJ/mol your reference could be the homo-atomic molecular phase of the constituents, i.e. O2, N2, H2, and in whetever form C and P are normally bought by a chemistry lab. Another possibility is to compare with isolated atoms, this gives you the binding energy of the crystal. I suspect the details are somewhere in [1]. > I do use nc pseudopotentials and my system is composed of > triphenylphosphine moities with aminobenzoic acids connected. In any case, you MUST use the same pseudopotential and cutoffs when doing the reference calculation for the comparison to be useful. bests -- Lorenzo Paulatto IdR @ IMPMC/UPMC CNRS & Universit? Paris 6 phone: +33 (0)1 44275 084 / skype: paulatz www: http://www.impmc.upmc.fr/~paulatto/ mail: 23-24/4?14 Bo?te courrier 115, 4 place Jussieu 75252 Paris C?dex 05
