Simple model of hydrogen and lithium chemisorption on jellium substrates

Within a simple one-parameter quasianalytic model, we are able to reproduce the main one-body features of first-principles calculations for hydrogen chemisorption on jellium surfaces. These include the qualitative variation in the width and position of the resonance peaks as the adatom-substrate separation is allowed to change. The general variation of these features with the electron density of the substrate is also reproduced with remarkable accuracy. Preliminary results for Li adsorption are also presented, and also seem to be compatible with the limited data from first-principles calculations. Nevertheless the limitation of the present model to an $l=0\mathrm{}$ solution means that it cannot include $\mathrm{sp}$-hybridization effects which appear to be important. The simplicity of the current model enables a simple physical interpretation of the mechanism of chemisorption on free-electron-like substrates. In addition there is a strong possibility of extension of our model to systems, of greater practical importance, for which a first-principles calculation is as yet not possible.