Equation 11 states that the absolute chemical potential of a solution is determined by three quantities: µ 0 i , the standard chemical potential; µ ex i , the excess chemical potential of the component at a concentration of χ; and a volume-dependent ideal gas component of k B T • ln (Λ 3 i • N ASA /〈V 〉 solut ion ). µ 0 ASA only required information regarding the internal structure of the molecule , thus we estimated µ 0 ASA by alchemically transforming a single solute molecule into a single Einstein molecule (Table ), whose absolute free energy we know how to calculate. We used the same number of states that we chose for the solid state simulations and we found that µ 0 ASA is equal to -150.7(2) k B T, as discussed in the last subsection of the Methods section.