A water molecule consists of an oxygen atom with a hydrogen atom on each side. The smaller of the two angles between the two \(\mathrm{OH}\) bonds is \(108^{\circ}\). Find the distance of the center of mass of a water molecule from the oxygen atom in terms of the distance \(d\) between the oxygen atom and either hydrogen atom. The \(\mathrm{O}\) has 16 times the mass of each \(H\).