Lateral thermal expansion of Cu(110) surface studied with helium atom scattering

Lateral thermal expansion of the Cu(110) surface is investigated by helium atom scattering. The expansion coefficients in the [001] direction are eval uated from high-resolution helium diffraction measurements to be 2.02 x 10( -5) and 2.35 x 10(-5) K-1 under vacuum and under atomic hydrogen irradiatio n, respectively. In the presence of the atomic hydrogen the thermal expansi on is enhanced by 1.4, consistent with previous observations of softening o f Cu-Cu bonding. (C) 1999 Elsevier Science B.V. All rights reserved.