  Metallic solids are a challenging target for wavefunction-based electronic
structure theories and have not been studied in great detail by such methods.
Here, we use coupled-cluster theory with single and double excitations (CCSD)
to study the structure of solid lithium and aluminum using optimized Gaussian
basis sets. We calculate the equilibrium lattice constant, bulk modulus, and
cohesive energy and compare them to experimental values, finding accuracy
comparable to common density functionals. Because the quantum chemical "gold
standard" CCSD(T) (CCSD with perturbative triple excitations) is inapplicable
to metals in the thermodynamic limit, we test two approximate improvements to
CCSD, which are found to improve the predicted cohesive energies.
