End-point calculation of solvation free energy of amino-acid analogs by molecular theories of solution

The computational efficiency is improved for the solvation free energy when the calculation is restricted to the initial and final states of the solute insertion process (pure solvent and solution systems of interest). We explore the possibility of such ‘end-point’ calculations and assess the performance of several approximate free-energy functionals against benchmarks for amino-acid analogs in water. The performance is the best and the second, respectively, for the method of energy representation and the RISM (reference interaction site model)/partial-wave expansion supplemented by semi-empirical corrections for the excluded-volume and hydrogen-bonding effects, while the chemical accuracy is not achieved for the others.