Alkane dissociation dynamics on Pt(110)--(1[times]2)
- Department of Chemical Engineering, Stanford University, Stanford, California 94305 (United States)
Supersonic molecular beam techniques were used to study the reactive adsorption dynamics of methane and ethane on Pt(110)--(1[times]2). The initial dissociative sticking probability, [ital S][sub 0], was measured as a function of surface temperature, incident translational energy, incident total vibrational energy, and incident polar angle at two azimuthal orientations. Under all experimental conditions, both alkanes dissociated via direct collisional activation. Over the range of translational energies studied here neither [ital S][sub 0](CH[sub 4]) nor [ital S][sub 0](C[sub 2]H[sub 6]) exhibited a dependence on nozzle temperature in these experiments suggesting that excitation of the normal vibrational motions of methyl deformation, methyl rocking, C--C stretching, and torsional vibrational modes do not play a significant role in the direct dissociation of either alkane on Pt(110)--(1[times]2) under these experimental conditions. The C--H stretching modes were not sufficiently populated to determine the extent of their participation. Methane and ethane displayed almost identical initial reaction probabilities at a fixed incident translational energy and polar angle, similar to our findings for methane and ethane dissociation on Pt(111). However, the reactivity of both species was about a factor of 2 [ital lower] on Pt(110)--(1[times]2) than observed on Pt(111) at a fixed incident translational energy and polar angle. When the crystal was positioned such that the tangential velocity component of the beam was incident along the atomic rows (the [1[bar 1]0] direction) the dissociation of both alkanes exhibited normal energy scaling.
- DOE Contract Number:
- FG03-86ER13468
- OSTI ID:
- 6606971
- Journal Information:
- Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 98:12; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ADHESION
ADSORPTION
ALKANES
BEAMS
CHEMICAL BONDS
CHEMICAL REACTIONS
COLLISIONS
DISSOCIATION
ELEMENTS
ENERGY DEPENDENCE
ENERGY LEVELS
ETHANE
EXCITED STATES
FLUID FLOW
HYDROCARBONS
METALS
METHANE
MOLECULAR BEAMS
MOLECULE COLLISIONS
ORGANIC COMPOUNDS
PLATINUM
PLATINUM METALS
PROBABILITY
SORPTION
SUPERSONIC FLOW
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS
VIBRATIONAL STATES