WORK FUNCTION OF RYDBERG MATTER SURFACES FROM JELLIUM CALCULATIONS

The theoretical description of Rydberg matter as an electronically exc ited type of matter was given by Manykin et al. [Sov. Phys. Tech. Phys . 26 (1981) 974; Sov. Phys. JETP 57 (1983) 256]. Experiment studies of Rydberg matter of Cs with principal quantum numbers, estimated to be around n = 15 from the life-time and temperature range where Rydberg m atter is stable, give work functions less than 0.7 eV. Solid-state den sity-functional calculations of work functions using pseudopotential t echniques for Rydberg matter of Cs give values less than 0.2 eV at n > 15 (Manykin et al. [Sov. Phys. JETP 75 (1992) 440, 6021). Jellium cal culations give work function values in general agreement with the more complex solid-state calculations due to Manykin et al. We now present more accurate work functions based on the Rydberg matter densities re cently calculated by Manykin et al. It is shown that jellium theory gi ves consistently lower work functions than the more complex solid-stat e theory. This is not unexpected due to the larger volume per valence electron. The close agreement between the two strongly different model s indicates that the true work function is close to and probably sligh tly higher than predicted by Manykin et al.