Hello everyone,

Despite my search in Material Studio help manual, Discover manual and internet resources, I am unable to find the explicit definition of the intramolecular energy as used by Material Studio. In the Material Studio help manual it is stated that the cohesive energy is Uintra-(Ucalc+dUtail). Unfortunately, it seems that this occurrence of “intramolecular energy” is the only one I can find. As a matter of convention, the definition of intramolecular energy as given by computational methods differs among scientific papers as well as common usage physical chemistry books. I would like to be sure which one of the following convention is used by Material Studio.

1) A first convention consists in the equivalence of Uintra=Ubonding=Ubond+Uangle+Udihedral+Ucrossterms and

Uinter=Unonbond.

I made several test calculations, and I think I can discard this possibility for Material Studio.

2) Another convention is that

Uintra=Ubonding+Unonbond(1,4) [(1,4) denotes that the considered atoms are in the same molecule and separated by 3 successive bonds]

In this convention, the subsequent nonbond interactions (1,5), (1,6) etc... inside a single molecule are considered as contribution to the intermolecular interaction.

Uinter=Unonbond(1,5)+Unonbond(1,6)+...+Unonbond-between-molecules

3) Finally, according to the Physical Chemistry book (Levine), the intermolecular term is associated to all the attractions and repulsions between the molecules, thus

Uintra=Ubonding+Unonbond(1,4)+ Unonbond(1,5)+Unonbond(1,6)+...

Uinter= Unonbond-between-molecules

I would like to know which one of these three definitions is used by Material Studio. I would be thankful if someone could provide me the answer or references that could help me determine it.

Best regards,

François