Accession Number:

ADA220566

Title:

Electronic Structure and Lubrication Properties of MoS2: a Qualitative Molecular Orbital Approach

Descriptive Note:

Corporate Author:

AEROSPACE CORP EL SEGUNDO CA CHEMISTRY AND PHYSICS LAB

Report Date:

1990-03-21

Pagination or Media Count:

35.0

Abstract:

The electronic structure of the solid lubricant material MoS2 is described by a qualitative molecular orbital MO model that is based on the D2h symmetry of the MoS6 unit in the crystal. The MO model is used to assign peaks in the valence-level photoelectron spectrum VLPS and the electron energy loss spectrum of MoS20001 and to interpret the effects of ion bombardment IB of this surface on its electronic structure. The dependence of VLPS peak intensities on excitation energy is used to assign the energy levels in the MO diagram. Variations in crystal lattice spacing within sputter-deposited MoS2 films are explained in terms of electron density arguments. Structural information, together with information on surface bonding and on adhesion from the IB studies, aids in predicting the lubrication performance of these films. It is proposed that the highest occupied orbital for MoS2 is an A1 nonbonding orbital and that important film properties, such as adhesion to substrates and friction within the film, can be manipulated by altering the electron occupancy of this orbital. JHD

Subject Categories:

  • Lubricants and Hydraulic Fluids
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE