UCL Chemistry

Closing date: 1st July 2012
Summary: Applications are invited for a 4 year EngD in theoretical chemistry, hosted by the Industrial Doctorate Centre in Molecular Modelling and Materials Science in the UCL Department of Chemistry and sponsored by the Nuclear Decommissioning Agency. The successful applicant will use both density functional and ab initio methodologies in order to perform relativistic quantum-chemical investigations of complexes relevant to An(III)/Ln(III) separation technologies.

Closing date: Friday 15th June 2012
Summary: Applications are invited for an EPSRC-funded 4-year PhD studentship in the area of computational materials science based in the UCL Industrial Doctorate Centre in Molecular Modelling and Materials Science. Novel materials for biomedical applications, such as hard tissue replacement implants, are based on mimicking the structure and properties of the natural tissue – in this case bone – as closely as possible. Understanding of the natural growth process is therefore crucial but difficult to access experimentally, which is where computer modelling becomes vitally important.

Closing date: 1st July 2012
Summary: Applications are invited for a PhD studentship in the area of modelling radiation damage in semiconducting and insulating materials. The modification of materials by irradiating with ions, photons and electrons impacts many areas of science and technology, including nanotechnology, nuclear technology and high resolution imaging. In some scenarios this modification is beneficial, as in nanostructuring material surfaces with ion beams, and in other cases it is detrimental to material properties, as in radiation damage of nuclear materials.

Summary: Several PhD positions in theoretical chemistry are available involving the application and development of electronic structure techniques to problems in nanotechnology relating to the interfacial properties of water and ice.

Summary: Applications are invited for Research Engineers for the Engineering Doctorate Centre in Molecular Modelling and Materials Simulation. The Engineering Doctorate Centre is jointly run by the Departments of Chemistry, Earth Sciences and Physics and the Birkbeck Industrial Materials Group. All the Departments have significant (internationally-leading) research programmes in the area of materials computer modelling over a range of length- and time-scales.

Closing date: 01/07/2012
Summary: A 42-month PhD position in theoretical chemistry is available within the research group of Dr. Martijn Zwijnenburg, focusing on the application and development of electronic structure techniques for modelling the photochemistry of conjugated polymers.

Start: October 2012
Project Summary
Applications are invited for this 3 year Impact Studentship PhD jointly funded by UCL and Wallop Defence Systems Ltd. and hosted by the UCL Department of Chemistry. The successful applicant will undertake complementary experimental and computational studies on a series of models for energetic materials.

Prof D.A. Tocher and Prof S.L. Price will be the primary and secondary academic supervisors respectively while Dr R. Vrcelj will act as the industrial supervisor.

Project Details
The physical properties of a solid material are based almost entirely on its underlying structure. As such polymorphism (the ability to crystallise in more than one structure) in organic materials poses import questions. The nature of energetic materials requires a good understanding of the materials structure, and importantly an understanding of polymorph control.  This is particularly vital for the safety aspects of both manufacture and usage. One important property is the sensitivity to external stimuli.  A material which has a polymorph that is relatively insensitive to, say, electric spark, may have a polymorph that is very sensitive to such a stimulus.  A classic example is the material HMX, which has the relatively safe (and commonly used) polymorph β-HMX and the sensitive polymorph α-HMX (amongst others).

There are two aspects to understanding problems like these; firstly there is the experimental understanding, examination of crystallisation and understanding the polymorphic forms which occur under differing conditions, and secondly there is the theoretical analysis and further development of computational modelling to support the experimental data. The student undertaking this project will carry out both experimental on model compounds (selected to permit safe working in the laboratory) for materials important in the energetic industry. New forms will be sought via crystallisation screens and characterisation carried out using a range of techniques (PXRD, IR/Raman spectroscopy, hot stage microscopy). Computational studies will predict potential solid forms studies which may be used to aid solid state characterisation and potentially suggest new experimental methods (e.g. templating) that would increase the range of polymorphs. To gauge how effectively the methods for calculation of potential crystal structures, developed mainly for pharmaceutical materials in the past 10 years, work for energetic materials, we will perform initial studies upon two previously extensively experimentally studied energetic materials, HMX and RDX.

The position is only available to UK nationals who will graduate with a first or upper second class degree in a relevant subject (Chemistry, Physics, Materials Science). Research experience in either solid state characterisation or computational chemistry would be advantageous. The studentship covers fees and a maintenance grant at the standard EPSRC rate with London weighting. There is no defined closing date.

Further background on the activities of the research group is available at www.cposs.org.uk. Further information is available on the submission of a CV via email to d.a.tocher@ucl.ac.uk

The starting date for this project will be September 2012.
Summary: Applications are invited for a 3.5 year EPSRC funded PhD in theoretical chemistry hosted by the UCL Department of Chemistry. The successful applicant will use variants of the CASSCF methodology in order to perform relativistic quantum-chemical investigations of fundamental aspects of f-element bonding.

Closing date: Friday 15th June 2012
Summary: Applications are invited for an EPSRC-funded 4-year PhD studentship in the area of computational materials science based in the UCL Industrial Doctorate Centre in Molecular Modelling and Materials Science. Novel materials for biomedical applications, such as hard tissue replacement implants, are based on mimicking the structure and properties of the natural tissue – in this case bone – as closely as possible. Understanding of the natural growth process is therefore crucial but difficult to access experimentally, which is where computer modelling becomes vitally important.

Closing date: 1st July 2012
Summary: Applications are invited for a PhD studentship in the area of modelling radiation damage in semiconducting and insulating materials. The modification of materials by irradiating with ions, photons and electrons impacts many areas of science and technology, including nanotechnology, nuclear technology and high resolution imaging. In some scenarios this modification is beneficial, as in nanostructuring material surfaces with ion beams, and in other cases it is detrimental to material properties, as in radiation damage of nuclear materials.

Start: October 2012
Project Summary
Applications are invited for this 3 year Impact Studentship PhD jointly funded by UCL and Wallop Defence Systems Ltd. and hosted by the UCL Department of Chemistry. The successful applicant will undertake complementary experimental and computational studies on a series of models for energetic materials.

Prof D.A. Tocher and Prof S.L. Price will be the primary and secondary academic supervisors respectively while Dr R. Vrcelj will act as the industrial supervisor.

Project Details
The physical properties of a solid material are based almost entirely on its underlying structure. As such polymorphism (the ability to crystallise in more than one structure) in organic materials poses import questions. The nature of energetic materials requires a good understanding of the materials structure, and importantly an understanding of polymorph control.  This is particularly vital for the safety aspects of both manufacture and usage. One important property is the sensitivity to external stimuli.  A material which has a polymorph that is relatively insensitive to, say, electric spark, may have a polymorph that is very sensitive to such a stimulus.  A classic example is the material HMX, which has the relatively safe (and commonly used) polymorph β-HMX and the sensitive polymorph α-HMX (amongst others).

There are two aspects to understanding problems like these; firstly there is the experimental understanding, examination of crystallisation and understanding the polymorphic forms which occur under differing conditions, and secondly there is the theoretical analysis and further development of computational modelling to support the experimental data. The student undertaking this project will carry out both experimental on model compounds (selected to permit safe working in the laboratory) for materials important in the energetic industry. New forms will be sought via crystallisation screens and characterisation carried out using a range of techniques (PXRD, IR/Raman spectroscopy, hot stage microscopy). Computational studies will predict potential solid forms studies which may be used to aid solid state characterisation and potentially suggest new experimental methods (e.g. templating) that would increase the range of polymorphs. To gauge how effectively the methods for calculation of potential crystal structures, developed mainly for pharmaceutical materials in the past 10 years, work for energetic materials, we will perform initial studies upon two previously extensively experimentally studied energetic materials, HMX and RDX.

The position is only available to UK nationals who will graduate with a first or upper second class degree in a relevant subject (Chemistry, Physics, Materials Science). Research experience in either solid state characterisation or computational chemistry would be advantageous. The studentship covers fees and a maintenance grant at the standard EPSRC rate with London weighting. There is no defined closing date.

Further background on the activities of the research group is available at www.cposs.org.uk. Further information is available on the submission of a CV via email to d.a.tocher@ucl.ac.uk

Closing date: August 2012
Summary: Applications are invited for a 3-year Ph.D. studentship within the research group of Geoff Thornton at UCL and Phillipe Sautet at ENS-Lyon. Scanning Tunnelling Microscopy (STM) has revolutionised our understanding of surfaces by providing real space images with atomic resolution, while playing the dual role of manipulation tool and imaging device. Until recently, the technique lacked chemical specificity, requiring complementary spectroscopic tools such as FTIR, HREELS or photoemission to identify the species being imaged. However, in the past few years scanning tunneling spectroscopy (STS) and STM–IETS (STM Inelastic Electron Tunnelling Spectroscopy) have been developed as a powerful tool in the chemical analysis of single molecules and their reactions [1,2]. By recording the changes of conductance due to single-mode vibrational excitation, STM–IETS is capable of mapping the excitation of modes in real space with sub-Å spatial resolution and meV spectral resolution. In other words, STM-IETS can be used to measure the vibrational spectrum of a single molecule.  For instance, our results for N₂ on Cu(110) at 4 K show losses consistent with molecules at defect sites being chemisorbed, with those at regular lattice sites being physisorbed [3].

Closing date: Friday 15th June 2012
Summary: Applications are invited for an EPSRC-funded 4-year PhD studentship in the area of computational materials science based in the UCL Industrial Doctorate Centre in Molecular Modelling and Materials Science. Novel materials for biomedical applications, such as hard tissue replacement implants, are based on mimicking the structure and properties of the natural tissue – in this case bone – as closely as possible. Understanding of the natural growth process is therefore crucial but difficult to access experimentally, which is where computer modelling becomes vitally important.

Closing date: 1st July 2012
Summary: Applications are invited for a PhD studentship in the area of modelling radiation damage in semiconducting and insulating materials. The modification of materials by irradiating with ions, photons and electrons impacts many areas of science and technology, including nanotechnology, nuclear technology and high resolution imaging. In some scenarios this modification is beneficial, as in nanostructuring material surfaces with ion beams, and in other cases it is detrimental to material properties, as in radiation damage of nuclear materials.

Summary: Application are invited for 4 year PhD positions in Physical Chemistry hosted by UCL Chemistry Department in collaboration with the Physics Department. There are vacancies to work with groups based in Physical Chemistry. Applicants must expect to achieve a first or upper second class degree in Chemistry, Physics or other relevant subject and should satisfy the standard EPSRC UK residency requirements. The stipend is the standard EPSRC PhD student stipend plus London Allowance.

Closing date: 01/07/2012
Summary: A 42-month PhD position in theoretical chemistry is available within the research group of Dr. Martijn Zwijnenburg, focusing on the application and development of electronic structure techniques for modelling the photochemistry of conjugated polymers.

Closing Date for Applications: August 2012
Start Date: September 2012
Summary: A four-year studentship is available to work on an ERC funded project ‘Energy Functional Metal Oxide Surfaces’. It will focus on ultrafast interfacial energy-transfer processes associated with model photocatalysis and solar energy conversion involving TiO₂. The experiments will employ a combination of two-photon photoelectron emission (2PPE) using a range of wavelengths from the infrared (800 nm) to the ultraviolet (200 nm) and time-resolved ultrasoft X-ray photoemission (TRPES) measurements. The 2PPE experiments will extend measurements on TiO₂(110) with water and methanol to higher energies and will test a hypothesis that a wet electron state lies exactly 2.4 eV above the conduction band.

The TRPES measurements would first look at the time dependence of the band gap state of TiO₂(110) to test the idea that charge trapping by these states might be involved in the photocatalysis process. This will involve band gap excitation as a pump (UV), followed by a soft-X-ray pulse to provide photoemission. We will look for an increase in intensity of the band gap state, which lies at about 1 eV binding energy following the UV pump as a function of delay time. It is possible that other band gap states may appear populated by the decay of states in the conduction band occupied on excitation by the UV pulse. Dissipation may involve sub-surface atoms on the basis of our work and photoelectron diffraction measurements that point to delocalisation of the band gap state over several Ti atoms. The corresponding band gap states might be expected to have a different energy and/or time signature. In addition to the band gap state, we would also monitor in photoemission the O 2s signal as well as the Ti 3p shoulder at 1 eV higher binding energy that is characteristic of Ti3⁺ species. These signals might also be expected to demonstrate a time dependence on the fs timescale due to dissipation following the pump pulse.

Following our characterisation of dissipation in the substrate, attention would turn to modifications induced by exposure to water and oxygen. The band gap state is unchanged when water dissociates in the 10-8 mbar regime to form hydroxyl (OH) species, but changes to the time signature might be expected. Prior to the TRPES measurements, we would carry out UV exposure measurements using STM to gain an initial idea of the degree of dissociation or other modification. A Hg lamp would be used for this purpose. Exposure of the hydroxylated surface to O₂ evolves water into the gas phase at room temperature, leaving atomic O on the five-fold coordinated Ti. If this reaction is not taken to completion then intermediates such as peroxo species are formed. Exposure to H₂O below 200 K results in molecular adsorption.

By controlling the temperature and/or coadsorption to O2 we will be able to select particular adsorbates to examine with TRPES of the band gap state, valence band and shallow core levels. A comparison between these measurements and time-dependent calculations of the charge flow would provide unprecedented insight into these important interfacial processes associated with photocatalysis.

The calculations would involve a collaboration with Prof Nic Harrison at Imperial College London who has developed time dependent DFT code to deal with this type of system.

TRPES studies of the ordered overlayer on TiO₂(110) formed by immersion would form a natural extension to the surfaces created in UHV, and provide a step closer to the ‘real’ system.

The studentship is for four years with a tax-free stipend of GBP 15,590. The fees are paid.

Enquiries to Geoff Thornton g.thornton@ucl.ac.uk

Summary: The region between the stars, the interstellar medium (ISM), is not empty but is populated with a rich array of atoms, molecules and dust.1  The research field of astrochemistry aims to understand this rich chemical diversity by combining the expertise of astronomers, astrophysicists, chemists and physicists; a truly interdisciplinary effort to explain molecular synthesis in the interstellar medium. Interstellar chemistry is not just of interest in the physical sciences, these reaction pathways form not just small molecules, but also larger organic species which have been proposed as the precursors to life. When stars die, they spew atoms and dust into deep space. In the cold and dark of the ISM, gravity gradually pulls these atoms and dust together to form interstellar clouds: cold and tenuous aggregations of dust and gas.2-3 Our research programme seeks to understand the fascinating chemistry that occurs on the cold (10 K - 20 K) dust grains in these clouds, a chemistry which is dramatically different from that encountered on Earth.

We have funding, as part of the UCL-Impact scheme, for a PhD student to work at both UCL(UK) and Friedrich Schiller University (Jena, Germany) to investigate chemical processes on models of interstellar dust grains. At UCL we have developed an experiment to study the reactions of H and O atoms with the molecular ices that build up on interstellar dust grains. This thermal processing of molecular ices is thought to be a route to chemical complexity in the interstellar medium. For example, we have observed the formation of ethylene oxide when oxygen atoms react with ethene on a graphite surface at 15 K.4 Our experimental methodology allows us to extract the rates of these surface reactions for use in astrochemical models. As part of the proposed PhD project the student would further develop this experiment to allow the study of the reaction of N and possibly S atoms with a variety of typical interstellar ice molecules. These UCL-based investigations study the reaction on the “outer” surfaces of the ices, where the ice molecules interact with reactive species from the gas-phase. In complimentary work in Jena the student would investigate the chemical interactions between the grains and deposited ice layers containing astrophysically relevant molecules.  Such reactions between the grains and the overlying ice have not been studied to date. However, it is well known that UV irradiation can trigger reactions between molecules that are adsorbed on surfaces of grains and so UV light may also stimualte reacitons between the gains and the ice molecules. Eventually, solid layers can be formed on top of these particles.5 In silicates, for example Si-OH groups might be formed on the cold surfaces of silicate grains following the photolysis of water ice. In Jena the opportunity also is available to use the atom source developed at UCL to investigate how S atoms react with carbonaceous grains, again at the low temperatures of the ISM.
This studentship is equally funded by UCL and the Max-Planck Institute for Astronomy. We envisage the student will spend approximately equal amounts of time in the UK and in Germany.  UCL and Jena also form part of a large European collaboration on Laboratory Astrophysics.

A successful applicant will have a First or Upper Second Class Degree, or equivalent qualification, in a relevant discipline, and be resident in the EU.  For more information please contact Professor Price at UCL (s.d.price@ucl.ac.uk). There is no defined closing date and the post will be advertised until filled.

References:
1    DA Williams et al., Astron. Geophys. (2007) 48 25.
2    DA Williams et al., Surf. Sci. (2002) 500 823.
3    AGGM Tielens,  The Physics and Chemistry of the Interstellar Medium, Cambridge Unviersity Press, Cambridge, 2005.
4    MD Ward et al., The Astrophysical Journal (2011) 741 121.
5    Dartois et al. Astron. Astrophys. (2005) 432, 895. 

PhD Studentship (to start October 2012)
London Centre for Nanotechnology
University College London
Summary: Applications are invited for a 4-year PhD studentship. The aim of this project is to provide an understanding of the chemical physics of single-crystalline CeO2 in relation to hydrogen production.

Start: October 2012
Project Summary
Applications are invited for this 3 year Impact Studentship PhD jointly funded by UCL and Wallop Defence Systems Ltd. and hosted by the UCL Department of Chemistry. The successful applicant will undertake complementary experimental and computational studies on a series of models for energetic materials.

Prof D.A. Tocher and Prof S.L. Price will be the primary and secondary academic supervisors respectively while Dr R. Vrcelj will act as the industrial supervisor.

Project Details
The physical properties of a solid material are based almost entirely on its underlying structure. As such polymorphism (the ability to crystallise in more than one structure) in organic materials poses import questions. The nature of energetic materials requires a good understanding of the materials structure, and importantly an understanding of polymorph control.  This is particularly vital for the safety aspects of both manufacture and usage. One important property is the sensitivity to external stimuli.  A material which has a polymorph that is relatively insensitive to, say, electric spark, may have a polymorph that is very sensitive to such a stimulus.  A classic example is the material HMX, which has the relatively safe (and commonly used) polymorph β-HMX and the sensitive polymorph α-HMX (amongst others).

There are two aspects to understanding problems like these; firstly there is the experimental understanding, examination of crystallisation and understanding the polymorphic forms which occur under differing conditions, and secondly there is the theoretical analysis and further development of computational modelling to support the experimental data. The student undertaking this project will carry out both experimental on model compounds (selected to permit safe working in the laboratory) for materials important in the energetic industry. New forms will be sought via crystallisation screens and characterisation carried out using a range of techniques (PXRD, IR/Raman spectroscopy, hot stage microscopy). Computational studies will predict potential solid forms studies which may be used to aid solid state characterisation and potentially suggest new experimental methods (e.g. templating) that would increase the range of polymorphs. To gauge how effectively the methods for calculation of potential crystal structures, developed mainly for pharmaceutical materials in the past 10 years, work for energetic materials, we will perform initial studies upon two previously extensively experimentally studied energetic materials, HMX and RDX.

The position is only available to UK nationals who will graduate with a first or upper second class degree in a relevant subject (Chemistry, Physics, Materials Science). Research experience in either solid state characterisation or computational chemistry would be advantageous. The studentship covers fees and a maintenance grant at the standard EPSRC rate with London weighting. There is no defined closing date.

Further background on the activities of the research group is available at www.cposs.org.uk. Further information is available on the submission of a CV via email to d.a.tocher@ucl.ac.uk

The starting date for this project will be September 2012.
Summary: Applications are invited for a 3.5 year EPSRC funded PhD in theoretical chemistry hosted by the UCL Department of Chemistry. The successful applicant will use variants of the CASSCF methodology in order to perform relativistic quantum-chemical investigations of fundamental aspects of f-element bonding.