Temperature dependence of the spectrum of electrons levitating above solid hydrogen

Abstract

A theory of photoresonance transitions for the electrons localized above the solid H2 surface is proposed on the basis of the experimental data obtained by V. V. Zav’yalov and I. I. Smol’yaninov [Pis’ma Zh. Eksp. Teor. Fiz. 44, 142 (1986); Zh. Eksp. Teor. Fiz. 92, 339 (1987); Zh. Eksp. Teor. Fiz. 94, 307 (1988)] and a simple model of condensed hydrogen, H2. A new explanation is offered for the strong dependence of the transition frequency v on the hydrogen vapor pressure revealed in the above-cited works. In contrast to the notions that were proposed by V. V. Zav’yalov and I. I. Smol’yaninov [Zh. Eksp. Teor. Fiz. 92, 339 (1987); Zh. Eksp. Teor. Fiz. 94, 307 (1988)]; and V. B. Shikin and S. N. Nazin [Pis’ma Zh. Eksp. Teor. Fiz. 82, 752 (2005)] and based on the effects of the quantum refraction of electrons by hydrogen vapor atoms, the temperature dependence of the frequency ν = ν (T) is attributed here to the H2 vapor inhomogeneity. The nonanalytic dependence of ν on the vapor density nν, ν(nν) − ν(0) ∼ nνγ ∼ e−Δ/T, γ ≅ 0.56 has been revealed from the experimental data. The activation energy Δ corresponds to the “incomplete evaporation” of solid hydrogen [see J. I. Frenkel, Z. Phys. 26, 37 (1924); Kinetic Theory of Liquids (Nauka, Leningrad, 1945; Clarendon, Oxford, 1946)]. The parameter Δ is lower than the energy of the “complete evaporation” of solid H2 equal to 92.6 K.