Electronic structure of liquid transition metals studied by time resolved photoelectron spectroscopy

Abstract

The electronic structure of liquid transition metals has been studied by time resolved photoelectron spectroscopy. Distinct changes in the valence band structure across the solid-liquid phase transitions have been observed for Pd, Mo and W. In the case of Pd the changes on melting are caused by a change in the photoemission process itself. For Nb, Mo, Ta and W we suggest a change in the atomic short range order from the bcc structure to an fcc-like short range order in the liquid state which causes a marked change in the valence band spectra of Mo and W due to the filling up of the pronounced gap in the density of states near the Fermi level. The measurements show that time resolved photoelectron spectroscopy can be used to study high temperature oxidation processes on the microsecond time scale.

Time evolution of electron structure in femtosecond heated warm dense molybdenum

“…The 4d−band envelop is significantly affected when the temperature increases. The structures disappear to form a fairly flat and slightly broadened band, as illustrated in the calculation performed at 20,000 K. Such behavior is observed at temperatures as low as 4,000 K confirming that it is highly correlated with the transition from solid to liquid phase, as previously reported in photoelectron spectroscopy measurements 34,35 . The decrease in density results in a negative energy shift of both the 4d−band and the Fermi energy E F .…”

Melting of aluminum, molybdenum, and the light actinides

“…show changes in the DOS in the solid and liquid which reflect the changes in atomic ordering from bcc to a close-packed-like ordering [23][24][25].…”

Sound velocity in shock compressed molybdenum obtained byab initiomolecular dynamics

“…On the basis of extensive experimental [1][2][3][4][5][6][7][8][9][10][11] and theoretical studies of the phase diagram of Mo the following can be safely concluded. The body-centered cubic (bcc) phase of Mo is extremely stable up to very high pressures, at least in excess of 5 Mbars.…”