Search for charge density waves in potassium using electron energy loss spectroscopy.

The technique of electron energy loss spectroscopy is well adapted to a search for charge density waves (CDW's) in alkali metals since it couples preferentially to dipole oscillators perpendicular to the surface. Measurements on clean K films in the energy hbaromega 1.2 eV reveal no CDW features. On exposure to H(2)0 or 0(2), losses are observed which are readily attributable to either adsorbate or phonon vibrations.