Two- to three-dimensional transition intermediate:: growth of benzene on Ru(001) and Mo(100)

The complex phase transitions of physisorbed benzene on Ru(001) and Mo(100) have been investigated using temperature programmed desorption (TPD), metastable impact electron spectroscopy (MIES) and work function measurements. The phase transition from benzene molecules whose planes are parallel to the surface to molecules with their planes approximately perpendicular to the surface is governed by a reversible two-dimensional gas-solid transition in the first physisorbed benzene layer. Furthermore, an additional phase of loosely bound benzene molecules, which can be considered as a two- to three-dimensional transition intermediate, is identified. (C) 1999 Elsevier Science B.V. All rights reserved.