Liquid Rb micrometric droplets confined in paraffin wax: an X-ray absorption spectro-scopy study

We have performed high-quality X-ray absorption measurements on crystalline (c-Rb) and liquid (l-Rb) Rubidium in the range from 15 K to 320 K. Perform ing a consistent analysis that takes into account the contribution of the m edium range structure, we observe that the l-Rb spectrum is compatible with pair correlation function g(r) previously determined by neutron diffractio n experiments. Due to the micrometric size of the liquid droplets we were a ble to observe a slight undercooling down to 290 K. We were also able to st udy the details of the very strong multielectron excitations channels in te rms of resonances, edges and shake-off features at proper theoretical energ y values.