Abstract

The mercury atom has a 5d¹⁰ 6s² dosed electronic shell configuration. Diatomic Hg₂ and other small mercury dusters arc predominantly van der Waals bound systems. However, the electronic structure changes strongly with increasing cluster size and finally converges towards the bulk, where the 6s and 6p bands overlap, giving mercury its metallic properties. This means, for the Hg_n-cluster a size dependent transition from van der Waals to covalent to metallic bonding exists. Mercury dusters were produced in a cold supersonic molecular beam using the seeded beam technique and were ionized by femtosecond laser pulses of 90-120fs time duration and of 1μJ up to 1mJ energy in the wavelength range 310nm to 800nm generated in a Ti:Sapphire system and a modelocked dye laser system(CPM). A Time of Flight (TOF) detector was used to measure the cluster-size distributions and to determine the released kinetic energy of the ionic fragments.

© 1996 IEEE