Comment on "First-principles determination of the bonding mechanism and adsorption energy for CO/MgO(001)" [Chem. Phys. Lett. 290 (1998) 255]

The interaction of CO on MgO has attracted much interest from theoretical and experimental researchers in recent years. All computational work agrees that at very low coverage, i.e. for isolated CO molecules, the bonding to the substrate is very weak, <0.1 eV. This result is obtained only with explicitly correlated wavefunctions or with density functional methods that include gradient corrections. The local density approach used in a recent Letter by Chen et al. [Chem. Phys. Lett. 290 (1998) 255] is therefore inadequate to solve this problem, despite what is claimed by these authors.