A density functional theory study of the CH2I2 reaction on Ag(111): Thermodynamics, kinetics, and electronic structures

Density functional theory calculation was performed to study the adsorption and reaction of CH2I2 on Ag(111). Thermodynamically favorable reactions of CH2I2 on Ag(111) are C-I bond ruptures and CH2 coupling to form ethylene. The energy barriers for the C-I bond ruptures of chemisorbed CH2I2 on Ag(111) are 0.43-0.48 eV, whereas the activation energy for the C-H bond rupture of chemisorbed CH2 on Ag(111) is 1.76 eV. The coupling reaction barrier of neighboring chemisorbed CH2 to form C2H4 on Ag(111) was much less than those of the C-I bond ruptures of CH2I2(a) and the migration of chemisorbed CH2 on Ag(111). The adsorption behaviors of different surface species on Ag(111) were well explained in terms of the charge density difference. (C) 2010 American Institute of Physics. [doi:10.1063/1.3292641]