[Pw_forum] Rydberg to KJ/mole

[Guntram Schmidt]

Hello together,

I'm sure, this question has been already asked - but lacking a search 
function for the pw_forum and not having found something using google, 
I'm urged to ask this question to the list:

How do I convert the output of pwscf (which is in Ry) to kJ per mole?

Conversion to Joules seems to be not a question, using pen&pencil or 
some tools (e.g., 
http://www.chemie.fu-berlin.de/chemistry/general/units_en.html).

Do I have to multiply the outcome with the avogadro number to get KJ/mol?

If so, I'm wondering about the outcome of my calculations. I have two 
sets of two polymorphic molecular crystals. The have energy differences 
of 0.09492046 Ry and 0.21669732 Ry, resp. . This would correspond to ca. 
120 and 280 kJ/mole! This would exceed the expected energy differences 
of polymorphs (10-25 kJ/mole) by one order of magnitude!

Did I miss something? Has there some other normalisation to be made?

Thanks a lot for help,
Guntram