Hx. Shao et al., PROBING THE HIGHLY CORRELATED MIXED-VALENT STATE VIA CHARGE-TRANSFER WITH ATOMS MOVING OUT FROM A SURFACE, Physical review letters, 77(5), 1996, pp. 948-951
We present physical arguments and quantitative calculations which indi
cate that under certain conditions atoms moving near metal surfaces ex
hibit a dramatic temperature and velocity dependence caused by a colle
ctive (mixed-valent) state. Charge transfer experiments are proposed t
o observe this phenomenon.