Stephen J Jenkins

Computational discovery of novel oxide-based X-ray detectors at University of Birmingham on FindAPhD.com PhD Project - Computational discovery of novel oxide-based X-ray detectors at University of Birmingham, listed on FindAPhD.com

PLEASE REPOST: We have a 4-year, fully funded PhD studentship focussed on using computational chemistry to find new and improved oxides for X-ray detection, to start in October 2025. findaphd.com/phds/project.... This is open only to UK nationals.

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Views from Dunnottar Castle

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Dunnottar Castle, Aberdeenshire

One trajectory can be seen here, where beige, dark green, light green, and white spheres represent silicon, chlorine, fluorine, and hydrogen atoms respectively. Here, you can see the formation of a hydrogen difluorochlorate molecule, which then forms a dihydrogen bond with the surface.

Vertiginous view looking down onto an enclosed bay with beach and rocks.

View through a glazed window onto a rocky bay.

View through a circular gunloop, looking onto battlements with a glimpse of sea beyond.

Views from Dunnottar Castle

Black and white image of ruined castle buildings perched on a rocky outcrop in centre of frame, with sea and sky beyond and either side. A path leads toward the castle from the left foreground.

Black and white image of ruined castle buildings perched on a rocky outcrop toward the left of frame, with sea and sky beyond and to the right. Rugged terrain in foreground.

Largely black and white image of ruinous stone walls, layered into the distance. In the mid foreground, a single clump of green plant-life with tiny orange flowers is in colour.

Black and white image of ruinous stone walls in foreground, looking up to a conically roofed circular turret and gabled building beyond.

Dunnottar Castle, Aberdeenshire

Mechanistic diversity in the reactive adsorption of chlorine trifluoride on monohydrogenated silicon We present first-principles molecular dynamic simulations of chlorine trifluoride impinging upon the monohydrogenated Si{001} surface. Our computed trajectories reveal a rich variety of reactive adsor...

Announcing the publication of our latest paper – “Mechanistic Diversity in the Reactive Adsorption of Chlorine Trifluoride on Monohydrogenated Silicon” – free to download from @pccp.rsc.org #ChemSky #CompChemSky

Meanwhile, it would be great if some brave experimentalists were willing to risk exposing their apparatus to chlorine trifluoride, in order to test our predictions!

The chemical modification of semiconductor surfaces is often an important step in the manufacture of electronic devices, and although we are currently driven by fundamental curiosity, we hope that insights from our work may one day have practical applications in this industry.

All of which leads us to the conclusion that the reactions of this particular molecule with this particular surface are markedly diverse, leading to a variety of different surface fluorine environments that we are currently investigating in greater depth for a future publication.

In another trajectory, two fluorine atoms attach to the surface, while another pings off into space – alone save for a nearby molecule of hydrogen chloride. In other trajectories, we see the formation of such species as hydrogen fluoride and chlorine monofluoride.

One trajectory can be seen here, where beige, dark green, light green, and white spheres represent silicon, chlorine, fluorine, and hydrogen atoms respectively. Here, you can see the formation of a hydrogen difluorochlorate molecule, which then forms a dihydrogen bond with the surface.

In around half of our simulated trajectories, we find that the molecule undergoes a reaction within about a picosecond (a millionth of a millionth of a second) of arriving at the surface, releasing lots of energy as it does so.

In our work, we used quantum mechanical calculations of interatomic forces to conduct simulations (much safer than experiments) of individual molecules arriving at a hydrogen-passivated silicon surface. Most molecules would simply bounce off, but not chlorine trifluoride.

It’s been considered for use by rocket scientists and nuclear scientists but discarded by both because it’s just too dangerous. Nevertheless, it does find a use in the semiconductor industry, as a cleaning agent for the equipment used in growing multi-layered devices.

Sand Won't Save You This Time

There’s a great introductory article about chlorine trifluoride by @dereklowe.bsky.social‬, which you might like to read for more detail, but basically the stuff reacts violently with almost anything – metal, sand, water, you name it.

For a number of years, we’ve been fascinated by the reactions of strong oxidants (ozone, fluorine, oxygen difluoride) with semiconductor surfaces, and this time our attention has been caught by a downright beast of a molecule, namely chlorine trifluoride.

Mechanistic diversity in the reactive adsorption of chlorine trifluoride on monohydrogenated silicon We present first-principles molecular dynamic simulations of chlorine trifluoride impinging upon the monohydrogenated Si{001} surface. Our computed trajectories reveal a rich variety of reactive adsor...

Announcing the publication of our latest paper – “Mechanistic Diversity in the Reactive Adsorption of Chlorine Trifluoride on Monohydrogenated Silicon” – free to download from @pccp.rsc.org #ChemSky #CompChemSky

#ChemSky for visibility...

Periodic Tower of Elements | LEGO® Ideas "Unleash Your Creativity: Craft the Universe’s Building Blocks with the 3D Periodic Tower of Elements! Dive into a world where chemistry, physics, and architect…

Everything would be awesome if we could build the Catz periodic spiral in LEGO! A design has been created & needs 10k votes before LEGO will consider it so let's get voting at ideas.lego.com/proje.... Learn about the original: caths.cam.ac.uk/abou... @chemlibcam.bsky.social‬ ‪@chemistryworld.com‬

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Mosaic flooring displaying a geometric pattern. Disjoint semicircles in white and red sit within a black cartouche. This is surrounded by a beige background, within black lines forming a lozenge shape.

Mosaic flooring displaying a geometric pattern of knots and lozenges in black, red, and beige.

Mosaic flooring showing geometric shapes in black, red, yellow, and beige.

Late-Roman or Visigothic mosaic flooring beneath the Mezquita, Cordoba #MosaicMonday

#ChemSky #CompChemSky

First-Principles Dynamics of the Surface Fluorination of Diamond We present first-principles dynamic simulations of molecular fluorine dissociatively adsorbing on clean C{001} and identify a range of possible outcomes depending upon the interplay of impact site, molecular orientation, and surface temperature. These include adsorption of a single fluorine atom with desorption of the other, in which case both the surface and the isolated atom gain radical character. In most scenarios, however, both fluorine atoms adsorb, either at opposite ends of a single surface dimer or on two such dimers. In the former situation the reaction end-point is closed-shell in nature, whereas in the latter the surface acquires singlet diradical character.

Our new paper on “First-Principles Dynamics of the Surface Fluorination of Diamond” is now published by Langmuir and available for download.

Mosaic flooring displaying a geometric pattern. A circle picked out in black, quartered in red and yellow, sits on a white background within black lines forming a lozenge shape.

Mosaic flooring displaying a geometric pattern. Disjoint semicircles in white and red sit within a black cartouche. This is surrounded by a beige background, within black lines forming a lozenge shape.

Mosaic flooring displaying a geometric pattern of knots and lozenges in black, red, and beige.

Mosaic flooring showing geometric shapes in black, red, yellow, and beige.

Late-Roman or Visigothic mosaic flooring beneath the Mezquita, Cordoba #MosaicMonday

Google AI overview of a paper on the surface fluorination of diamond, wrongly citing its authors as Helen Thake and Sean Jenkins. These should be Henry Thake and Stephen Jenkins.

Incidentally, Google AI is being its usual reliable self. Not sure who Helen Thake and Sean Jenkins might be, but the actual first author was Henry, not Helen, who carried out the work during his undergraduate project with yours truly (Stephen, not Sean) last year.

In both cases, deeper understanding of the reaction mechanism by which fluorine atoms may be deposited on the surface (either via F₂ molecules or in some other form) can only be beneficial in efforts to optimise the process.

Secondly, efforts toward using diamond in high-temperature semiconductor devices has long been hampered by the problem of controllably doping it (adding impurities to modify its electronic properties). Doping with fluorine on the surface of a thin diamond film holds some promise.

Aside from simple curiosity, our work on this topic is driven by a couple of potential applications. Firstly, it is known that fluorinated diamond surfaces are not only hydrophobic (water repellent) but also exhibit very low-friction – a great combination for industrial coatings.