Structures of chlorine on palladium (111)

Experimental structure determination of the chemisorbed overlayers of chlorine and iodine on Au{111}

“…This is only 0.05Å larger than the sum of the covalent radii of gold and iodine (1.44Å and 1.35Å) and 0.06Å smaller than the bond length of 2.90Å predicted theoretically 19 but very different from the bond length, 2.62Å, in the linear chain of AuI 35 . As I is less electronegative than the Cl one would expect a more covalent bond between Au and I and a bond length in accordance with findings of previous studies on chlorine adsorption on fcc transition metals that show metal-halogen bond lengths approximately equal to the sum of the covalent radii of halogen and metal atoms 17,33,[36][37][38][39] . Strong ionic interaction should cause disturbance to the Au{111} substrate.…”

Density functional study of Ni bulk, surfaces and the adsorbate systems Ni(111)R30°–Cl, and Ni(111)(2×2)–K

“…An effective radius for Cl on Ni(111) could be computed by subtracting an effective nickel radius of 3 48 ).…”

Chlorofluorocarbon dechlorination on Pd(111): effect of chlorine stoichiometry

“…Exposures to chlorine at higher temperatures, however, can give rise to higher coverages [11]. At this coverage the ratio of the Cl 2p peak area to the Pd 3d peak area was I Cl /I Pd = 0.018.…”

“…Molecular desorption of CF 3 CCl 3 was not observed until the coverage reached the point that θ Cl > 0.3 ML. Chlorine coverage was determined by calibrating the area under the Cl 2p X-ray photoemission (XP) peak with respect to that of the Cl-saturated Pd surface having θ Cl = 0.43 [11]. At high coverage some fraction of the adsorbed CF 3 CCl 3 desorbs at 184 K. The desorption energy that one would estimate from this peak, E des , is 47.5 kJ/mol; however, this is not necessarily the intrinsic desorption energy that one would get from the clean Pd(111) surface.…”

“…This enables us to make a direct measurement of the rate of C-Cl bond cleavage and thus a direct measurement of the intrinsic barrier to dechlorination, E C-Cl . The C-Cl cleavage kinetics can be studied by obtaining Cl 2p XP spectra during heating of the CF 3 ure are the Cl 2p XP spectra of multilayer CF 3 CCl 3 and a 0.43 ML coverage of atomic Cl produced by exposure to Cl 2 gas [11]. The figure clearly shows the evolution of the Cl 2p XP peak position and linewidth as the temperature increases from 90 to 250 K. At 90 K the XP spectrum of the CF 3 CCl 3 monolayer is similar to that of the multilayer; however, the shoulder at ∼ 198 eV indicates that there has been some lowtemperature dissociation of CF 3 CCl 3 on the Pd surface.…”