CLASSICAL ENERGY CALCULATIONS WITH ELECTRON CORRELATION OF CONDENSED EXCITED-STATES - RYDBERG MATTER

A classical model is used to calculate the work function and the bindi ng energy in condensed excited states, also named Rydberg Matter. The quantum mechanical description due to Manykin et al. shows that an exc ited matter exists, in which Rydberg states interact to give a gaseous metallic material with very low work function. Experimental evidence on a macroscopic level exists. In the present classical model, the ele ctron correlation is included by assuming a fixed distance between the excited electrons. This distance is equal to the interatomic spacing, and the electrons move coherently in circular orbits. The calculation s are done for different cluster sizes, with the emphasis on planar cl usters. Such clusters have recently been identified experimentally. Th e angular momentum of the orbiting electrons is smaller than the maxim um possible, i.e. the orbit diameter is smaller than the interatomic d istance. This means that the Rydberg atoms are still at a distance whi ch is 40% larger than the orbit diameter, when the energy for the elec trons starts to increase due to repulsion. The calculated work functio n is somewhat smaller than the Q.M. value in the range of interatomic distances used, and it agrees almost exactly with jellium calculations at large interatomic distances. The binding energy is a factor of 1.5 -3 smaller than the Q.M. one. The electrostatic interaction gives enou gh attraction to start the condensation of a dilute gas of Rydberg sta tes at large distance between the Rydberg atoms. It is shown that reta rdation effects due to the finite speed of light will not be important for very highly excited clusters, nor the interaction of the magnetic dipoles due to orbiting electrons. (C) 1998 Elsevier Science B.V. All rights reserved.