Each molecule in the set has at least one aromatic ring with the most being four aromatic rings in bifonazole (4). While the number of aromatics play an important role in drug design, for this work, the number of aromatics will affect the degree and type of noncovalent interactions available between the drug and toluene thus effecting logPtol/w values. Experimental measurement of logPtol/w values are described by Zamora et al. These are noted as molecules 1-16 as shown in Figure . Table contains the drug molecule name with the label and the SMILES strings, which were the starting point for the challenge. The SMILES strings were converted to XYZ coordinates using Open Babel. Figure . 2D structures of the sixteen SAMPL9 challenge molecules. A vertical solvation method has been shown to be an effective method to predict logPo/w as part of the SAMPL5 and SAMPL6 competitions when combined with more rigorous quantum mechanical methods, e.g., DLPNO-CCSD(T), or ab initio composite approaches, e.g., the correlation consistent Composite Approach (ccCA). The vertical solvation method is shown as Equation ,