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Reilly C, Hutchison A, Sitz GO. Survival of rotational alignment in H 2 scattering from Si(100). J Chem Phys 2021; 155:174705. [PMID: 34742218 DOI: 10.1063/5.0068518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We report a state-prepared, state-resolved study of rotational scattering of a diatomic molecule from a solid surface. Specifically, H2 molecules with 80 meV kinetic energy are rotationally aligned in the j = 3 rotational state via stimulated Raman pumping and then scattered from a Si(100) surface at normal incidence. The rotational alignment of the scattered molecules is determined by measuring, for both the incident and scattered molecules, the ionization yield of a probe laser, tuned to selectively ionize molecules in the j = 3 rotation level, as the probe laser polarization is rotated. The measurement is performed for two initial rotational alignments: a "helicoptering" alignment with the bonds constrained to lie primarily parallel to the surface and a "cartwheeling" alignment with the bonds lying primarily normal to the surface. For both initial alignments, the modulation of the probe ionization yield with laser polarization for the scattered molecules is pronounced, although significantly weaker than the modulation measured for the incident molecules. This indicates a significant modification but not a complete elimination of the initial alignment. The modulation is found to be stronger for the scattered molecules originating in the cartwheeling alignment than for the helicoptering alignment. These results contribute toward an improved understanding of the role of rotational motion in molecule-surface dynamics.
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Affiliation(s)
- Christopher Reilly
- Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA
| | - Andrew Hutchison
- Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA
| | - Greg O Sitz
- Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA
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2
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Bohamud T, Reutzel M, Dürr M, Höfer U. Dynamics of proton transfer reactions on silicon surfaces: OH-dissociation of methanol and water on Si(001). J Chem Phys 2019; 150:224703. [PMID: 31202240 DOI: 10.1063/1.5092804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The reaction dynamics of methanol and water on Si(001) were investigated by means of molecular beam techniques. The initial sticking probability s0 was determined as a function of the kinetic energy of the incoming molecules, Ekin, and surface temperature, Ts. For both, methanol and water, a nonactivated reactional channel was observed; the dynamics were found to be determined by the reaction into the datively bonded intermediate state. A low conversion barrier was deduced for the conversion from this intermediate into the final state. It is attributed to the reaction mechanism, which proceeds via proton transfer from the OH-group of the datively bonded molecules to a Si surface atom. Despite this low conversion barrier, adsorption into the intermediate and further reaction via proton transfer were found to be largely decoupled.
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Affiliation(s)
- T Bohamud
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - M Reutzel
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - M Dürr
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - U Höfer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, D-35032 Marburg, Germany
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3
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Reutzel M, Lipponer M, Dürr M, Höfer U. Binding Energy and Dissociation Barrier: Experimental Determination of the Key Parameters of the Potential Energy Curve of Diethyl Ether on Si(001). J Phys Chem Lett 2015; 6:3971-3975. [PMID: 26722901 DOI: 10.1021/acs.jpclett.5b01510] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The key parameters of the potential energy curve of organic molecules on semiconductor surfaces, binding energy of the intermediate state and dissociation barrier, were experimentally investigated for the model system of diethyl ether (Et2O) on Si(001). Et2O adsorbs via a datively bonded intermediate from which it converts via ether cleavage into a covalently attached final state. This thermally activated conversion into the final state was followed in real-time by means of optical second-harmonic generation (SHG) at different temperatures and the associated energy barrier ϵa = 0.38 ± 0.05 eV and pre-exponential factor νa = 10(4±1) s(-1) were determined. From molecular beam experiments on the initial sticking probability, the difference between the desorption energy ϵd and ϵa was extracted and thus the binding energy of the intermediate state was determined (0.62 ± 0.08 eV). The results are discussed in terms of general chemical trends as well as with respect to a wider applicability on adsorbate reactions on semiconductor surfaces.
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Affiliation(s)
- Marcel Reutzel
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , D-35032 Marburg, Germany
| | - Marcus Lipponer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , D-35032 Marburg, Germany
| | - Michael Dürr
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , D-35032 Marburg, Germany
- Institut für Angewandte Physik, Justus-Liebig-Universität Giessen , D-35392 Giessen, Germany
| | - Ulrich Höfer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , D-35032 Marburg, Germany
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4
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Lipponer M, Dürr M, Höfer U. Adsorption dynamics of tetrahydrofuran on Si(0 0 1) studied by means of molecular beam techniques. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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5
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Reaction Dynamics of Molecular Hydrogen on Silicon Surfaces: Importance of Lattice Degrees of Freedom. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/978-3-642-32955-5_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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6
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Kottke M, Neuburger M, Fee D, Beyer J, Pullman D. Observation of an exceptionally high apparent kinetic order in the thermal desorption of D2from the Si(100) surface. Mol Phys 2012. [DOI: 10.1080/00268976.2012.695809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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7
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Lipponer MA, Armbrust N, Dürr M, Höfer U. Adsorption dynamics of ethylene on Si(001). J Chem Phys 2012; 136:144703. [DOI: 10.1063/1.3700180] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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8
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Choi JH, Kim KS, Cho JH. Antiferromagnetic spin ordering in the dissociative adsorption of H2 on Si(001): density-functional calculations. J Chem Phys 2009; 131:244704. [PMID: 20059096 DOI: 10.1063/1.3276916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The dissociative adsorption of an H(2) molecule on the Si(001) surface, which has been experimentally identified in terms of dissociation on one side of two adjacent Si dimers, is investigated by spin polarized density-functional calculations within the generalized-gradient approximation. In contrast to the prevailing nonmagnetic configuration of charge ordering, we propose a new ground state where the two single dangling bonds (DBs) created by H(2) dissociation are antiferromagnetically coupled with each other. Such a spin ordering is found to be energetically favored over the previously proposed charge ordering. In the latter configuration, the buckling of the two DBs amounts to a height difference (Delta h) of 0.63 A, caused by a Jahn-Teller-like distortion, while in the former configuration, their buckling is almost suppressed to be Delta h=0.03 A as a consequence of spin polarization.
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Affiliation(s)
- Jin-Ho Choi
- Department of Physics and Research Institute for Natural Sciences, Hanyang University, 17 Haengdang-Dong, Seongdong-Ku, Seoul 133-791, Republic of Korea
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9
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Bisson R, Dang TT, Sacchi M, Beck RD. Vibrational activation in direct and precursor-mediated chemisorption of SiH4 on Si(100). J Chem Phys 2008; 129:081103. [DOI: 10.1063/1.2976563] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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10
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Chapter 16 Growth and Etching of Semiconductors. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s1573-4331(08)00016-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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11
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Frischkorn C, Wolf M. Femtochemistry at metal surfaces: nonadiabatic reaction dynamics. Chem Rev 2007; 106:4207-33. [PMID: 17031984 DOI: 10.1021/cr050161r] [Citation(s) in RCA: 274] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Christian Frischkorn
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany.
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Shi J, Chuan Kang H, Tok ES, Zhang J. Evidence for hydrogen desorption through both interdimer and intradimer paths from Si(100)-(2 x 1). J Chem Phys 2007; 123:34701. [PMID: 16080749 DOI: 10.1063/1.1937392] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Despite intensive work there are still controversial issues about desorption and adsorption of hydrogen on Si(100)-(2 x 1). In particular, the relative importance of the various interdimer- and intradimer-desorption paths is not clear. Nanosecond-pulse-laser desorption data have been used to argue that the 4H interdimer path is important, while data from thermal-desorption time-of-flight measurements suggest a large translationally hot contribution which cannot arise from the 4H interdimer path. The observation of a translationally hot desorption fraction at low to medium coverage can be accounted for by including the 2H interdimer path in quantum dynamical calculations. In this paper we investigate this issue further and present evidence that supports the inclusion of the intradimer path. Specifically, our results show that the intradimer and 3H interdimer paths provide the major contributions to the translationally hot fraction in the desorbate. Our conclusions are based on density-functional calculations of hydrogen translational excitation, mean-field analysis of thermal-desorption experiments over a range of ramp rate, and Monte Carlo simulations of nanosecond-pulse-laser experiments.
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Affiliation(s)
- J Shi
- Department of Chemistry, National University of Singapore
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13
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Niida T, Tsurumaki H, Namiki A. Desorption dynamics of deuterium molecules from the Si(100)-(3x1) dideuteride surface. J Chem Phys 2006; 124:024715. [PMID: 16422634 DOI: 10.1063/1.2141953] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We measured polar angle (theta)-resolved time-of-flight spectra of D2 molecules desorbing from the Si(100)-(3x1) dideuteride surface. The desorbing D2 molecules exhibit a considerable translational heating with mean desorption kinetic energies of approximately 0.25 eV, which is mostly independent of the desorption angles for 0 degrees<or=theta<or=30 degrees. The observed desorption dynamics of deuterium was discussed along the principle of detailed balance to predict their adsorption dynamics onto the monohydride Si surface.
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Affiliation(s)
- T Niida
- Department of Electrical Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550, Japan
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14
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Matsuno T, Niida T, Tsurumaki H, Namiki A. Coverage dependent desorption dynamics of deuterium on Si(100) surfaces: Interpretation with a diffusion-promoted desorption model. J Chem Phys 2005; 122:024702. [PMID: 15638609 DOI: 10.1063/1.1829994] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We studied coverage dependence of time-of-flight (TOF) spectra of D2 molecules thermally desorbed from the D/Si(100) surface. The mean translational energies Et of desorbed D2 molecules were found to increase from 0.20+/-0.05 eV to 0.40+/-0.04 eV as the desorption coverage window was decreased from 1.0 ML> or =thetaD> or =0.9 ML to 0.2 ML> or =thetaD> or =0 ML, being consistent with the kinetics switch predicted in the interdimer mechanism. The measured TOF spectra were deconvoluted into 2H, 3H, and 4H components by a curve fitting method along the principle of detailed balance. As a result, it turned out that the desorption kinetics changes from the 4H to the 3H situation at high coverage above thetaD=0.9 ML, while the 2H desorption is dominant for a quite wide coverage region up to thetaD=0.8 ML. A dynamic desorption mechanism by which the desorption is promoted by D-atom diffusion to dangling bonds was proposed.
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Affiliation(s)
- T Matsuno
- Department of Electrical Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550, Japan
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15
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Dürr M, Höfer U. Molecular beam investigation of hydrogen dissociation on Si(001) and Si(111) surfaces. J Chem Phys 2004; 121:8058-67. [PMID: 15485270 DOI: 10.1063/1.1797052] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The influence of molecular vibrations on the reaction dynamics of H2 on Si(001) as well as isotopic effects have been investigated by means of optical second-harmonic generation and molecular beam techniques. Enhanced dissociation of vibrationally excited H2 on Si(001)2 x 1 has been found corresponding to a reduction of the mean adsorption barrier to 390 meV and 180 meV for nu=1 and nu=2, respectively. The adsorption dynamics of the isotopes H2 and D2 show only small differences in the accessible range of beam energies between 50 meV and 350 meV. They are traced back to different degrees of vibrational excitation and do not point to an important influence of quantum tunneling in crossing the adsorption barrier. The sticking probability of H2 on the 7 x 7-reconstructed Si(111) surface was found to be activated both by H2 kinetic energy and surface temperature in a qualitatively similar fashion as H2/Si(001)2 x 1. Quantitatively, the overall sticking probabilities of H2 on the Si(111) surface are about one order of magnitude lower than on Si(001), the influence of surface temperature is generally stronger.
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Affiliation(s)
- M Dürr
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, D-35032 Marburg, Germany
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16
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Park WK, Park SC. 3D Generalized langevin equation approach to gas–surface reactive scattering: model H+H→H2/Si(100)-(2×1). ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0166-1280(03)00171-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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17
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Tok ES, Engstrom JR, Kang HC. Precursor states of atomic hydrogen on the Si(100)-(2×1) surface. J Chem Phys 2003. [DOI: 10.1063/1.1536959] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Lee JY, Maeng JY, Kim A, Cho YE, Kim S. Kinetics of H2 (D2) desorption from a Ge(100)-2×1:H (D) surface studied using scanning tunneling microscopy and temperature programmed desorption. J Chem Phys 2003. [DOI: 10.1063/1.1531662] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Filippi C, Healy SB, Kratzer P, Pehlke E, Scheffler M. Quantum Monte Carlo calculations of H2 dissociation on Si(001). PHYSICAL REVIEW LETTERS 2002; 89:166102. [PMID: 12398737 DOI: 10.1103/physrevlett.89.166102] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2002] [Indexed: 05/24/2023]
Abstract
The dissociative adsorption of H2 on the Si(001) surface is theoretically investigated for several reaction pathways using quantum Monte Carlo methods. Our reaction energies and barriers are at large variance with those obtained with commonly used approximate exchange-correlation density functionals. Our results for adsorption support recent experimental findings, while, for desorption, the calculations give barriers in excess of the presently accepted experimental value, pinpointing the role of coverage effects and desorption from steps.
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Affiliation(s)
- Claudia Filippi
- Instituut Lorentz, Universiteit Leiden, Niels Bohrweg 2, NL-2333 CA, The Netherlands
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20
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Sagara T, Kuga T, Tanaka K, Shibataka T, Fujimoto T, Namiki A. Translational heating of D(2) molecules thermally desorbed from Si(100) and Ge(100) surfaces. PHYSICAL REVIEW LETTERS 2002; 89:086101. [PMID: 12190484 DOI: 10.1103/physrevlett.89.086101] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2002] [Indexed: 05/23/2023]
Abstract
The translational energies of D(2) molecules thermally desorbed from the Si(100) and Ge(100) surfaces under a heating rate of 6 K/s have been measured. In contrast to the previous laser desorption study, results show a considerable translational heating; the observed translational temperature is about 3 times higher than the desorption temperature for both surfaces. This fact indicates that energy barriers for adsorption are present even in the desorption pathway. Detailed balance is applicable to the adsorption and desorption dynamics of hydrogen on the Si(100) surface.
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Affiliation(s)
- T Sagara
- Department of Electrical Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550, Japan
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21
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Dürr M, Biedermann A, Hu Z, Höfer U, Heinz TF. Probing high-barrier pathways of surface reactions by scanning tunneling microscopy. Science 2002; 296:1838-41. [PMID: 12052951 DOI: 10.1126/science.1070859] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The ability of scanning tunneling microscopy to probe the pathways of thermally activated high-barrier surface processes is frequently limited by competing low-barrier processes that can confuse measurement of the true initial and final configuration. We introduce an approach to circumvent this difficulty by driving the surface process with nanosecond laser heating. The method is applied to determine the pathway of recombinative desorption in the H/Si(001) system. The observed configuration of dangling bonds after laser heating reveals that the desorbed hydrogen molecules are not formed on single dimers, but rather from neighboring silicon dimers via an interdimer reaction pathway.
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Affiliation(s)
- M Dürr
- Departments of Physics and Electrical Engineering, Columbia University, New York, NY 10027, USA.
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22
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Dürr M, Höfer U. Stereochemistry on Si(001): angular dependence of H2 dissociation. PHYSICAL REVIEW LETTERS 2002; 88:076107. [PMID: 11863921 DOI: 10.1103/physrevlett.88.076107] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2001] [Indexed: 05/23/2023]
Abstract
The angular dependence of the dissociative adsorption of molecular hydrogen at terrace and step sites of vicinal single-domain Si(001) surfaces was investigated by means of molecular beam techniques and optical second-harmonic generation. A strongly anisotropic behavior was observed for terrace adsorption with polar distributions of cos3theta and cos12theta parallel and perpendicular to the dimer, respectively. The D(B)-steps show enhanced reactivity under glancing incidence in the upwards direction. The results are traced back to the directionality of the covalent surface bonds.
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Affiliation(s)
- Michael Dürr
- Max-Planck-Institut für Quantenoptik, D-85740 Garching, Germany
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23
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Yata M, Uesugi-Saitow Y. Activated dissociation via a trapping precursor: O2/Cu(001)-(2√×√)-O. J Chem Phys 2002. [DOI: 10.1063/1.1434951] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Dürr M, Hu Z, Biedermann A, Höfer U, Heinz TF. Real-space study of the pathway for dissociative adsorption of H2 on Si(001). PHYSICAL REVIEW LETTERS 2002; 88:046104. [PMID: 11801144 DOI: 10.1103/physrevlett.88.046104] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2001] [Indexed: 05/23/2023]
Abstract
Dissociative adsorption of molecular hydrogen on clean Si(001) surfaces has been investigated by means of scanning tunneling microscopy. The dissociated hydrogen atoms are found to occupy Si atoms of adjacent dimers. In addition to this interdimer configuration associated with the adsorption of isolated hydrogen molecules, pairs of adjacent doubly occupied dimers are readily formed. They arise from the enhanced reactivity of partially occupied dimers following the initial H2 adsorption step. The results are considered in light of recent adsorption and desorption measurements.
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Affiliation(s)
- M Dürr
- Physics Department, Columbia University, New York, New York 10027, USA
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25
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Okamoto Y. Hybrid Density-Functional Calculations of the Reactions of a H2 Molecule on C, Si, and Ge(001) Surfaces. J Phys Chem B 2001. [DOI: 10.1021/jp010996f] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yasuharu Okamoto
- Fundamental Research Laboratories, NEC Corporation, Tsukuba, Ibaraki 305-8501, Japan
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26
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Tok ES, Kang HC. Reaction path for hydrogen adsorption and desorption on Si(100)-(2×1). J Chem Phys 2001. [DOI: 10.1063/1.1402168] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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27
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Steckel JA, Phung T, Jordan KD, Nachtigall P. Concerted Use of Slab and Cluster Models in an ab Initio Study of Hydrogen Desorption from the Si(100) Surface. J Phys Chem B 2001. [DOI: 10.1021/jp0035176] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. A. Steckel
- Department of Chemistry and Center for Molecular and Materials Simulations, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - T. Phung
- Department of Chemistry and Center for Molecular and Materials Simulations, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - K. D. Jordan
- Department of Chemistry and Center for Molecular and Materials Simulations, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - P. Nachtigall
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic and Center for Complex Molecular Systems and Biomolecules, Dolejškova 3, 182 23 Prague 8, Czech Republic
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28
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Dürr M, Raschke MB, Pehlke E, Höfer U. Structure Sensitive Reaction Channels of Molecular Hydrogen on Silicon Surfaces. PHYSICAL REVIEW LETTERS 2001; 86:123-126. [PMID: 11136109 DOI: 10.1103/physrevlett.86.123] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2000] [Indexed: 05/23/2023]
Abstract
The ability of the Si(001) surface to adsorb H2 molecules dissociatively increases by orders of magnitude when appropriate surface dangling bonds are terminated by H atoms. Through molecular beam techniques the energy dependent sticking probability at different adsorption sites on H-precovered and stepped surfaces is measured to obtain information about the barriers to adsorption, which decrease systematically with an increase in coadsorbed H atoms. With the help of density functional calculations for interdimer adsorption pathways, this effect is traced back to the electronic structure of the different adsorption sites and its interplay with local lattice distortions.
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Affiliation(s)
- M Dürr
- Max-Planck-Institut für Quantenoptik, D-85740 Garching, Germany
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29
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Zimmermann FM, Pan X. Interaction of H2 with Si(001)-(2 x 1): solution of the barrier puzzle. PHYSICAL REVIEW LETTERS 2000; 85:618-621. [PMID: 10991354 DOI: 10.1103/physrevlett.85.618] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2000] [Indexed: 05/23/2023]
Abstract
The sticking probability of H2 on Si(001) is immeasurably small at room temperature, indicating the presence of a large energy barrier to adsorption. Surprisingly, the final state energy distributions of H2 molecules desorbing from Si(001) show no signs of having traversed such a barrier, in apparent contradiction with microscopic reversibility. Here we report experimental and theoretical evidence resolving this long-standing puzzle. Adsorption and desorption proceeding along two distinct, microscopically reversible pathways can explain all observations.
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Affiliation(s)
- F M Zimmermann
- Department of Physics and Laboratory for Surface Modification, Rutgers University, Piscataway, New Jersey 08854, USA
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