  We demonstrate that the melting points and other thermodynamic quantities of
the alkali metals can be calculated based on static crystalline properties. To
do this we derive analytic interatomic potentials for the alkali metals fitted
precisely to cohesive and vacancy energies, elastic moduli, lattice parameter
and crystal stability. These potentials are then used to calculate melting
points by simulating the equilibration of solid and liquid samples in thermal
contact at ambient pressure. With the exception of lithium, remarkably good
agreement is found with experimental values. The instability of the bcc
structure in Li and Na at low temperatures is also reproduced, and, unusually,
is not due to a soft T1N phonon mode. No forces or finite temperature
properties are included in the fit, so this demonstrates a surprisingly high
level of intrinsic transferrability in the simple potentials. Currently, there
are few potentials available for the alkali metals, so in, addition to
demonstrating trends in behaviour, we expect that the potentials will be of
broad general use.
