The ab initio neon-water potential-energy surface and its relationship with the hydrophobic hydration shell

The neon-water system has been investigated by ab initio quantum-chemical calculations. The potential-energy surface (PES) far the I:1 Ne-H2O interaction has been scanned at the MP2(full) level, with the 6-311 + + G(3df,2pd) basis set augmented with bond functions located midway between Ne and O. The most stable neon-water arrangement has r = 320 pm, theta = 120 degrees, with a counterpoise-corrected binding energy of -0.54 kJ mol(-1). The PES is otherwise quite flat (with binding energies of ca. -0.4 kJ mol(-1)) for all a values if r > ca. 310 pm. The off-plane, perpendicular approach is unfavourable. NMR shielding and the electric field gradient at all nuclei show only very small changes with respect to the isolated components.