  The Lifshitz theory of van der Waals forces is utilized for the systematic
calculation of the non-retarded room temperature Hamaker constants between 26
identical isotropic elemental metals that are embedded in vacuum or in pure
water. The full spectral method, complemented with a Drude-like low frequency
extrapolation, is employed for the elemental metals benefitting from the
availability of extended-in-frequency reliable dielectric data. The simple
spectral method is employed for pure water and three dielectric representations
are explored. Numerical truncation and low frequency extrapolation effects are
shown to be negligible. The accuracy of common Lifshitz approximations is
quantified. The Hamaker constants for 100 metal combinations are reported; the
geometric mixing rule is revealed to be highly accurate in vacuum and water.
