title: Adsorption and reactions of ClCH2CH2OH on clean and oxygen-precovered Cu(100): experimental and computational studies.
abstract: Temperature-programmed reaction/desorption, reflection-absorption infrared spectroscopy, and density functional theory calculations have been employed to investigate the adsorption and thermal reactions of ClCH2CH2OH on clean and oxygen-precovered Cu(100) surfaces. On Cu(100), ClCH2CH2OH is mainly adsorbed reversibly. The ClCH2CH2OH molecules at a submonolayer coverage can change their orientation with increasing temperature. However, on oxygen-precovered Cu(100), all of the adsorbed ClCH2CH2OH molecules below 0.5 langmuir exposures completely dissociate to generate ethylene and acetaldehyde via the intermediate of ClCH2CH2O-. The computational studies predict that the ClCH2CH2O- is most likely to be adsorbed at the 4-fold hollow sites of Cu(100), with its C-O bond only slightly titled away from the surface normal and with a gauche conformation with respect to the C-C bond. The hollow-site ClCH2CH2O- has an adsorption energy that is 4.4 and 19.2 kcal x mol(-1) lower than that of the ClCH2CH2O- bonded at the bridging and atop sites, respectively. No significant effect of precovered oxygen on the ClCH2CH2O- bonding geometry and infrared band frequencies has been observed, as compared with the case without oxygen.
authors.affiliation: Department of Chemistry, National Cheng Kung University 1, Ta Hsueh Road, Tainan, Taiwan 701, Republic of China.
authors.forename: Tao-Wei
authors.initials: TW
authors.lastname: Fu
authors.forename: Yung-Hsuan
authors.initials: YH
authors.lastname: Liao
authors.forename: Chia-Yuan
authors.initials: CY
authors.lastname: Chen
authors.forename: Pei-Teng
authors.initials: PT
authors.lastname: Chang
authors.forename: Ching-Yung
authors.initials: CY
authors.lastname: Wang
authors.forename: Jong-Liang
authors.initials: JL
authors.lastname: Lin
mesh_terms: D000327:Adsorption; D003198:Computer Simulation; D003300:Copper / Q000737:chemistry*; D005023:Ethylene Chlorohydrin / Q000737:chemistry*; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry*; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013499:Surface Properties; D013696:Temperature
chemical_list: D005023:Ethylene Chlorohydrin; D003300:Copper; D010100:Oxygen