What is the most reliable way to calculate mixing enthalpy of binary solvent mixture using GROMACS?
I have simulated two-component systems of water and organic solvent with GROMACS. In a research paper from my field of study, authors calculate 'enthalpy of mixing' with the software in order to compare it with experimental mixing enthalplies. Under the Experimental Section of the paper, authors show that they do this according to this term:
A comment added in the text says the following:
"The internal energy, U, of the liquid mixture was obtained directly from the potential energy (see Tables S1 and S2) during the simulation, and yi is the molar fraction of component i."
I am interested in calculating same thermodynamical properties for my systems. I am aware that I can do that with g_energy function in GROMACS, or at least some parts of it (Pressure, Volume, Potential Energy).
My question is: Firstly, is this an appropriate way of calculating enthalpy of mixing in GROMACS via this equation? Secondly, how can one specify with the g_energy function which of the liquid's U(or potential energy), P and V is calculated if I initiate the function with .edr files, i.e. how can I choose to calculate i'th component's properties?
Reference for the image and quote:
Aguilera-Segura, S. M.; Di Renzo, F.; Mineva, T. Structures, Intermolecular Interactions, and Chemical Hardness of Binary Water-Organic Solvents: A Molecular Dynamics Study. J. Mol. Model. 2018, 24 (10), 292. https://doi.org/10.1007/s00894-018-3817-2.