Chemisorption and physisorption of alkanethiols on Cu(111). A quantum mechanical investigation

被引:47
作者
Ferral, A
Paredes-Olivera, P
Macagno, VA
Patrito, EM
机构
[1] Univ Nacl Cordoba, Fac Ciencias Quim, Inst Invest Fisicoquim Cordoba, INFIQC,Dept Fisicoquim, RA-5000 Cordoba, Argentina
[2] Univ Nacl Cordoba, Fac Ciencias Quim, Inst Invest Fisicoquim Cordoba, INFIQC,Unidad Matemat, RA-5000 Cordoba, Argentina
关键词
chemisorption; copper; low index single crystal surfaces; ab initio quantum chemical methods and calculations; scanning tunneling microscopy;
D O I
10.1016/S0039-6028(02)02543-8
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The adsorption of n-alkanethiols on the 111 surface of copper was studied by means of quantum mechanical calculations. Charge transfer processes between the adsorbates and the metal were investigated in order to elucidate the nature of the adsorbed species. The electronic structure of the adsorbates in the proximity of the Fermi level was also investigated to obtain a better understanding of the electronic states which contribute to scanning tunneling microscopy (STM) images. We found that the bonding of the n-alkanethiols is independent of the chain length when the adsorbates are perpendicular to the surface. This bonding mainly involved the sulfur p-orbitals and, to a lesser extent, the orbitals of the first methyl group. From the analysis of dipole moment curves and Mulliken populations, a charge transfer of 0.6 electrons from the metal towards the adsorbate was obtained, thus confirming the anionic nature of the adsorbate. A depletion of electron density was observed in the metal atoms of the primary chemisorption site as well as a net accumulation of charge around the sulfur atom. Constant current STM images of thiols adsorbed flat on the surface showed a pronounced protrusion on the position of sulfur due to the accumulation of electron density around this atom in the proximity of the Fermi level. However, for thiols adsorbed perpendicular to the surface, the STM images were found to be sensitive to the position of the terminal methyl group. A corrugation of 1.5 Angstrom was obtained for a methyl radical adsorbed perpendicular to the surface. (C) 2002 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:85 / 99
页数:15
相关论文
共 84 条
[21]   Protective films on copper by multistep modification of an alkanethiol monolayer with chlorosilanes and alkanediol [J].
Haneda, R ;
Aramaki, K .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 1998, 145 (08) :2786-2791
[22]   Adsorption state of dimethyl disulfide on Au(111): Evidence for adsorption as thiolate at the bridge site [J].
Hayashi, T ;
Morikawa, Y ;
Nozoye, H .
JOURNAL OF CHEMICAL PHYSICS, 2001, 114 (17) :7615-7621
[23]   GEOMETRY AND BINDING OF ACETYLENE ON CU(111) - AB-INITIO CLUSTER STUDIES [J].
HERMANN, K ;
WITKO, M .
SURFACE SCIENCE, 1995, 337 (03) :205-214
[24]   THE ABINITIO MODEL POTENTIAL METHOD - MAIN GROUP ELEMENTS [J].
HUZINAGA, S ;
SEIJO, L ;
BARANDIARAN, Z ;
KLOBUKOWSKI, M .
JOURNAL OF CHEMICAL PHYSICS, 1987, 86 (04) :2132-2145
[25]   MODEL POTENTIAL METHOD IN MOLECULAR CALCULATIONS [J].
HUZINAGA, S ;
KLOBUKOWSKI, M ;
SAKAI, Y .
JOURNAL OF PHYSICAL CHEMISTRY, 1984, 88 (21) :4880-4886
[26]   GAUSSIAN-BASIS SETS FOR THE TRANSITION-METALS OF THE 1ST AND 2ND SERIES [J].
HYLAKRYSPIN, I ;
DEMUYNCK, J ;
STRICH, A ;
BENARD, M .
JOURNAL OF CHEMICAL PHYSICS, 1981, 75 (08) :3954-3961
[27]   Structural studies of adsorbed alkanethiols on Cu(111) by use of S and C K-edge X-ray absorption fine structures [J].
Imanishi, A ;
Isawa, K ;
Matsui, F ;
Tsuduki, T ;
Yokoyama, T ;
Kondoh, H ;
Kitajima, Y ;
Ohta, T .
SURFACE SCIENCE, 1998, 407 (1-3) :282-292
[28]   Permeability of alkanethiol self-assembled monolayers adsorbed on copper electrodes to molecular oxygen dissolved in 0.5 m Na2SO4 solution [J].
Ishibashi, M ;
Itoh, M ;
Nishihara, H ;
Aramaki, K .
ELECTROCHIMICA ACTA, 1996, 41 (02) :241-248
[29]   PREPARATION AND EVALUATION OF 2-DIMENSIONAL POLYMER-FILMS BY CHEMICAL MODIFICATION OF AN ALKANETHIOL SELF-ASSEMBLED MONOLAYER FOR PROTECTION OF COPPER AGAINST CORROSION [J].
ITOH, M ;
NISHIHARA, H ;
ARAMAKI, K .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 1995, 142 (11) :3696-3704
[30]   THE PROTECTION ABILITY OF 11-MERCAPTO-1-UNDECANOL SELF-ASSEMBLED MONOLAYER MODIFIED WITH ALKYLTRICHLOROSILANES AGAINST CORROSION OF COPPER [J].
ITOH, M ;
NISHIHARA, H ;
ARAMAKI, K .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 1995, 142 (06) :1839-1846