E(misfit), E(hb), E(vdW) and E(Int)

[gandhiforbes]

I am writing to inquire about how to obtain the values of E(misfit), E(hb), E(vdW), and E(Int). I would appreciate your guidance on this matter. Thank you.

[ianhbell]

Sorry I don't follow your question. Can you please expand?

[gandhiforbes]

Thanks for your reply.

Let me expand my queries:

E(misfit) stands for misfit energy which originates from the non-ideal contact of two segments. E(vdW) stands for Van der Waals’ energy which is a summation of dispersion energy and cavity formation energy. The cavity formation energy arises due to the formation of cavity inside conductor medium to accept a molecule from the gas phase to the conductor medium. The inhomogeneous charges on the molecular surface are adequately represented by the dispersion energy. E(hb) stands for hydrogen bond energy.

klamt2010.pdf

Eq. (1), (2) and (3) of the attached research article (VdW is not mentioned in this article).

I am interested in finding theses values for each molecule. Thanks.

[ianhbell]

I think this is not included in COSMO-SAC, at least it is not included in our implementation. I think this is obtained from the calculation that is used to obtain the sigma profile? But I acknowledge I am not an expert in these things.

[gandhiforbes]

Thanks for the reply. I was going through COSMO.hpp (located in include->COSMO_SAC). I observed that equation (1) (2) and (3) of the above-mentioned research article has been implemented between line number 143-166. Can we do something on this to get the required values?

[ianhbell]

Then you want to call the function .get_DELTAW() on your COSMO model instance

[ianhbell]

Some response from my collaborator on the COSMO-SAC implementation:

The misfit energy E_mf is part of the segment pair energy E_pair which is used in the formulation of the chemical potential in the original paper by Lin and Sandler. Translated to the segment activity coefficient this is one part of the exchange energy Delta W which consists of that misfit energy, hydrogen bonding energy and nonelectrostatic energies. The last term is neglected in the original COSMO-SAC. The misfit term is calculated differently in the different COSMO-SAC versions. I don't think it is a value that is accessible though as it is one part of Delta W which is only be used in those iterative sums to calculate the segment activity coefficients. Same goes for the hydrogen bonding energies.

The cavity formation energy is accounted for by the Staverman-Guggenheim combinatorial contribution. This is a value that should be accessible in that COSMO-SAC implementation.

The dispersive contribution is only being accounted for in the COSMO-SAC-dsp version. It should be an accessible value in that COSMO-SAC implementation as well.

[gandhiforbes]

Thanks for your suggestions.