  The Diffusion Monte Carlo (DMC) method is applied to compute the ground state
energies of the water monomer and dimer and their D 2 O isotopomers using
MB-pol; the most recent and most accurate ab inito- based potential energy
surface (PES). MB-pol has already demonstrated excellent agreement with high
level electronic structure data, as well as agreement with some experimental,
spectroscopic, and thermodynamic data. Here, the DMC binding energies of (H 2
O) 2 and (D 2 O) 2 agree with the corresponding values obtained from velocity
map imaging within, respectively, 0.01 and 0.02 kcal/mol. This work adds two
more valuable data points that highlight the accuracy of the MB-pol PES.
