Electron-induced dissociation of a fluorocarbon adsorbate CF (ad) at 4.6 K is shown by Scanning Tunnelling Microscopy (STM) to form directed energetic F-atom 'projectiles' on Cu(110). The outcome of a collision between these directed projectiles and stationary co-adsorbed allyl 'target' molecules was found through STM to give rotational excitation of the target allyl, clockwise or anti-clockwise, depending on the chosen collision geometry.
View Article and Find Full Text PDFChem Commun (Camb)
November 2021
An F-atom with ∼1 eV translational energy was aimed at a line of fluorocarbon adsorbates on Cu(110). Sequential 'knock-on' of F-atom products was observed by STM to propagate along the 1D fluorocarbon line. Hot F-atoms travelling along the line in six successive '' cycles paralleled the rocking of a macroscopic Newton's cradle.
View Article and Find Full Text PDFJ Phys Condens Matter
September 2021
The electron-induced dissociation of chemisorbed HS to give recoiling H-atoms was investigated on a Si(111)-7 × 7 surface at 270 K by scanning tunnelling microscopy and modelled by density functional theory. Two different H-atom migratory pathways were identified: 'short-range' (S-R; 37%) and 'long-range' (L-R; 42%). In S-R reaction the H-atom recoiled by only 4 Å whereas in L-R the average H-recoil distance was 17 Å extending up to 72 Å.
View Article and Find Full Text PDFReaction dynamics examines molecular motions in reactive collisions. The aiming of reagents at one another has been achieved at selected miss distances (impact parameters, ) by using the corrugations on crystalline surfaces as collimator. Prior experimental work and calculation showed single atoms aimed at chemisorbed molecules with = 0 gave knock-on of atomic reaction products through a linear transition state.
View Article and Find Full Text PDFIn Surface-Aligned-Reactions (SAR), the degrees of freedom of chemical reactions are restricted and therefore the reaction outcome is selected. Using the inherent corrugation of a Cu(110) substrate the adsorbate molecules can be positioned and aligned and the impact parameter, the collision miss-distance, can be chosen. Here, substitution reaction for a zero impact parameter collision gives an outcome which resembles the classic Newton's cradle in which an incident mass 'knocks-on' the same mass in the collision partner, here F + CF → (CF)' + (F)' at a copper surface.
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