We study how the binding energy, the vibrational frequencies and the adsorp
tion isotherm of CO on Pd(100) are modified when the solid is subject to un
iform strain. The parameters controlling the thermodynamics of adsorption (
the adsorption energy, the vibrational frequencies of the adsorbed molecule
s and the interaction energy between the molecules) have been calculated by
using density functional theory. These parameters are then used in a grand
canonical Monte Carlo simulation that determines the CO coverage when the
surface is in thermodynamic equilibrium with a CO gas, at a specified press
ure and temperature. We find that this is substantially affected by the str
ain. Our results, along with those obtained by others, suggest that the dev
elopment of "elastochemistry," a study of the change in the chemical proper
ties of a surface when subjected to strain will lead to interesting and mea
surable results. It also suggests that differences in chemical activity bet
ween clusters on a support and clusters in gas phase may be partly due to t
he strain induced when a cluster is placed on the support. (C) 2000 America
n Institute of Physics. [S0021-9606(00)00627-9].