  Surface plasmons subject to a surface distortion split asymmetrically in
energy resulting in a net lowering of zero-point energy. This is because
surface plasmon eigenvalues are the square of frequencies, a statement
generally true for electromagnetic excitations. We utilize the method based on
conformal mapping to demonstrate asymmetric splitting under surface
corrugations leading to a decrease in zero-point energy of a single corrugated
metallic surface contributing to surface reconstructions but too small on its
own to drive the reconstruction. However, by introducing a second metallic
surface more significant lowering of energy is seen sufficient to drive the
instability of a mercury thin film.
