Extended x-ray-absorption fine structure studies of levitated undercooled metallic melts

We report the first attempt to combine electromagnetic levitation with extended x-ray-absorption fine structure (EXAFS) spectroscopy for the determination of nearest-neighbor distances in the metastable state of an undercooled metallic melt. The experiments have shown that it is possible to measure EXAFS spectra for a freely suspended liquid droplet up to temperatures of 1390 degrees C. In particular, spectra at an undercooling of 325 degrees C were recorded. The spectra show certain differences between the overheated and the deeply undercooled regime. Modeling of the pair distribution function is required for correct interpretation, because asymmetric effects due to the large disorder in the hot liquid have to be considered. (C) 1996 American Institute of Physics.