Methyl on Cu(111)––structural determination including influence of co-adsorbed iodine

A DFT investigation of the adsorption of methyl on Rh(111)

“…One calculation [20] showed hcp site is 27 meV lower in energy while the other [19] showed hcp site is 10 meV higher in energy as compared with fcc site. Recently, the experimental investigations on CH 3 / Cu(1 1 1) performed by Pascal et al [21] revealed that the methyl groups do occupy the fcc hollow sites at low coverage, which is somewhat similar to our finding.…”

“…The chemisorption of methyl on transition metal surfaces has been extensively studied experimentally and theoretically [11][12][13][14][15][16][17][18][19][20][21]. Most of the investigations have focused on the C-H symmetric stretching mode of methyl adsorbed on metal surfaces, which are observed to be redshifted by several hundred wave numbers below a typical value of $2900 cm À1 in some cases.…”

“…Some experimental and theoretical investigations [11,16,[28][29][30][31][32] carried out on fcc(1 1 1) surfaces showed that CH 3 adopted a C 3v symmetry and tilting the molecule from C 3v to C s symmetry was not energetically favorable, while others [33][34][35] have suggested that the symmetry is only C s . Recently, the adsorption of methyl species on Cu(1 1 1) has been investigated by Pascal et al using scanned energy mode photoelectron diffraction [21]. They found that a methyl group is adsorbed on Cu(1 1 1) with C 3v symmetry, but the possibility that the species was tilted on the surface could not be excluded.…”

Chemisorption and Reaction Characteristics of Methyl Radicals on Cu(110)

“…This consideration is compatible with the finding for CH 3 on Cu(111) in which the radicals clearly prefer to occupy the 3-fold-coordinated hollow sites. 31 A possible chemisorption geometry of CH 3 -(ads) radicals on the (110) surface is illustrated in Figure 9, showing both the top and side views of surface structure. From the radii of C (r C ) and H (r H ) atoms and the H-C-H angle (θ HCH ) in the CH 3 (ads) radical, we can calculate the diameter of the methyl radicals to be 2(r C + 2r H ) cos(θ HCH -90°).…”

Density Functional Theory Study of Methyl Iodide Adsorption and Dissociation on Clean and K-Promoted β-Mo2C Surfaces

“…Since nickel is a catalyst for commercial steam reforming of methane, a lot of experimental and theoretical study is focused on the investigation of methyl groups on nickel surfaces; see, for example, ref 1. DFT calculations addressed the effect of coadsorbed iodine 2 and the decomposition pathway of CH fragments 3 as well. Taking into account that the activation of the C-H bond in methane requires high energy, while the C-I bond breaks rather easily, adsorbed methyl iodide has been used as a precursor for generation of methyl groups by thermal activation or photolysis on different metal surfaces.…”