Using high resolution electron energy loss spectroscopy, we have studied both the energy and angular dependence of vibrational losses for the surface formate species chemisorbed on Ni(110). Selective vibrational mode enhancement is found to occur at a primary electron beam energy of E i ≅ 14 eV. In particular, the intensity of the symmetric OCO stretching mode, v s(COO), at 167 meV, can be dramatically enhanced depending on both the choice of electron scattering angles and the angle of the electron scattering plane relative to the plane of the formate species. Not only is the fundamental vibration enhanced, but also the first two overtones and some combination bands. The results are interpreted in terms of the formation of a temporary negative ion, which is closely related to the so-called σ-shape resonance, observed in recent NEXAFS experiments of CO containing species.