Ionization potential of Al₆ and Al₇ as a function of temperature

Abstract.

The temperature-depence of the ionization potential of Al₆ and Al₇ clusters is studied by using ab initio molecular dynamics. The threshold regions of theoretical photoionization efficiency curves are obtained from the calculated ionization potential distributions by integration and the determined ionization potentials are compared with the experimental ones. Two important effects, which complicate the determination of ionization potential from photoionization efficiency curves, are observed: the thermal tail effect and the isomerization. Also a link between the adiabatic ionization potential and the threshold of the photoionization efficiency curve is discussed. In the case of Al₇, this often used connection breaks down.