Hello,

I previously contacted the Dassault systems technical support seeking clarification on treatment of multiple conformers in COSMOtherm/COSMO-RS and they directed me to this forum for support. 

I wanted to seek some clarification on how COSMOtherm treats multiple conformers when computing the free energy of solvation of a solute with multiple conformers in a given solvent. I have had a look at the COSMOtherm 2020 manual which provides equation 1.2-9 for computing the population of a conformer in solvent. However, I'm uncertain if I follow this equation correctly. The first term seems to be a Boltzmann weight based on the solution free energy of the conformer, which is dimensionless and less than 1, and the gas phase energy, which has units and is typically very large in magnitude, is then subtracted from this. I don't think this is what is done, and I'm additionally not clear on how these populations are then used in the computation of the free energy of solvation. May I ask how COSMOtherm is computing the free energy of solvation for multiple conformers, and how the free energy of solvation of each individual conformer is related to that of the ensemble? Thank you for your help.

Sincerely,

Angiras