¹³³Cs high pressure Mössbauer spectroscopy: a new powerful tool for studying charge transfer and lattice dynamics in metallic Cs

Abstract

The purpose of this paper is to illustrate that¹³³Cs high pressure Mössbauer effect (ME) spectroscopy is an ideal technique to investigate on a microscopic level the pressure effects on charge transfer and lattice dynamics in metallic Cs. After discussing the experimental difficulties, which have been the reason for the lack of¹³³Cs ME studies on metallic Cs since 1965, we show that the results reveal first direct microscopic evidence for a pressure induced 6s→ 5d electronic transition in metallic Cs. We further investigate the change of Debye temperature with pressure at 4.2 K and obtain a new value of the Debye temperature of metallic Cs of Θ_D = 64(2) K atp = 6 GPa. Special emphasis is given to the comparison of the experimental results with recent band structure calculations.