Ab initio studies of the electronic structure of l-cysteine adsorbed on Ag(111)

LUQUE, N.B.; VÉLEZ, P.; PÖTTING, K.; SANTOS, E.

AMER CHEMICAL SOC

Lugar: Washington; Año: 2012 vol. 28 p. 8084 - 8084

e have performed ab initio calculations for the adsorption of l-cysteine on Ag(111) using density functional theory. We have focused on two possible adsorbed species: the l-cysteine radical (?S-CH 2-CH-NH 2-COOH) adsorbed almost flat at a bridge site, slightly displaced toward an fcc location, and the zwitterionic radical Z-cysteine (?S-CH 2-CH-NH 3 +-COO -) adsorbed at a bridge site, shifted to a hcp site forming a (4 × 4) unit cell (θ = 0.06) and a (√3 × √3) R 30° unit cell (θ = 0.33), respectively. Special attention has been paid to the electronic structure of the system. The adsorbate-silver bond formation has been exhaustively investigated by analyzing the density of states projected onto the different atoms of the molecule, and by charge density difference calculations. A complicated interplay between sp and d states of silver in the formation of bonds between the adso