Analysis of the energy distributions of sulfur atoms and molecules laser-desorbed from the surface of a molybdenite single crystal

In the present work the energy distributions of neutral particles desorbed from a surface by a single laser pulse were measured by the double-transit method. With the help of this method the authors investigated the surface of an MoS2 single crystal, which has a layered structure. Materials of this class are characterized by strong anisotropy of the crystal structure and chemical bonds. The atomic planes of the crystal are combined into groups known as layers. Bonds between atoms within a layer are directed into the layer and are much stronger than the bonds between layers. Such structures are of direct interest, because they are a realization of two-dimensional systems. The compound MoS2 has a layered structure in which each layer consists of three atomic planes, so that a sheet of hexagonally packed Mo atoms is squeezed between two hexagonally packed sheets of sulfur. The relative orientation of the molybdenum and sulfur planes is such that a trigonal prismatic configuration forms around each metal atom. Photostimulated desorption from the MoS2 surface was studied with light-flux intensities that were too low to damage the material. In the present work they investigated the action of 15-ns pulses of the first-harmonic radiation (1,064 nm) of a YAG:Nd3+ laser