New Horizons in Chemical and Photochemical Dynamics
Lead Research Organisation:
University of Bristol
Department Name: Chemistry
Abstract
Chemical change, whether caused by collisions between reactive atoms, radicals and molecules, or by absorption of light (photochemistry), is of fundamental importance in all branches of Chemistry. For example, synthesis of complicated organic molecules, such as those naturally occurring in plant and animal life, or needed to construct functional modern materials, requires an in-depth understanding of reaction mechanisms to design synthetic pathways. Ideas from physical chemistry based on thermodynamics and reaction rate theory underpin our ability to predict directions of chemical change and how quickly such change will occur. The fields of chemical reaction and photodissociation have sought to place such theories on a quantitative foundation built on deep understanding of the quantum mechanics of breakage and formation of chemical bonds. Potential energy surfaces (PESs) (based on the Born-Oppenheimer separation of the fast motion of light electrons from the slower motion of heavier atomic nuclei) are an essential concept because they provide a map of the energy landscape(s) over which chemical change occurs. Minima and barriers on the PESs correspond, respectively, to stable conformations of the atoms and short-lived transition states. Photodissociation involves dynamics on PESs lying higher in energy than the lowest, ground state, with the extra energy needed to reach these excited states provided by absorption of light. A powerful driver for advances in understanding of the dynamics of photochemical and reactive processes has been a close interaction between experimental and theoretical studies - arguably, the field has done much to stimulate the development of theoretical methods to calculate PE landscapes and describe the molecular dynamics on these surfaces. Such methods (subject to simplifying approximations) are now finding widespread use in molecular modelling of, for example, drug design, enzyme catalysis, and many other fields. The historical development of experimental and theoretical methods has relied on complementary studies of systems with only a small number of atoms (e.g. photodissociation of diatomic and triatomic molecules; reaction of atoms with diatomic molecules) so that accurate PESs can be computed and precise, quantum-mechanical (QM) scattering calculations carried out. Such experiments were mostly conducted in the gas phase, in the low-temperature and rarefied environment of a molecular beam, so that complicating factors of solvation, or interaction between molecules can be ignored. Considerable success with such systems has, for example, revealed the importance of exotic QM effects in chemistry such as tunnelling through reaction barriers, scattering resonances, non-adiabatic coupling between PESs, and interference between different pathways to the same products. For a photochemical or reactive system with 3 atoms, only 3 coordinates are required to describe all the possible arrangements of the atoms and the associated PEs can thus be computed for representative configurations spanning the entire PE landscape. We now seek a multi-pronged approach to extend such studies to more complicated systems, with the intention of learning about PE landscapes for larger molecules (for N atoms, 3N-6 coordinates are needed to describe the associated PE hypersurface), the effects of jumps between PE surfaces, and to examine how the energy landscapes and chemical dynamics are changed in the presence of solvent. In so doing, we will bring the fields of reaction and photodissociation dynamics closer to the types of chemical reactions used in synthesis by organic, inorganic and biological chemists. Our strategy involves development of new experiments and theoretical methods. The substantial challenges necessitate a consortium-based approach, in which complementary expertise in two Universities is brought together to address selected problems from which we can learn much about chemical change.
Organisations
Publications
Harris S
(2014)
Transient electronic and vibrational absorption studies of the photo-Claisen and photo-Fries rearrangements
in Chem. Sci.
Harris S
(2015)
A Multipronged Comparative Study of the Ultraviolet Photochemistry of 2-, 3-, and 4-Chlorophenol in the Gas Phase
in The Journal of Physical Chemistry A
Harris SJ
(2013)
Comparing molecular photofragmentation dynamics in the gas and liquid phases.
in Physical chemistry chemical physics : PCCP
Hopkins WS
(2011)
RG+ formation following photolysis of NO-RG via the Ã-X transition: a velocity map imaging study.
in The Journal of chemical physics
John J
(2012)
PImMS, a fast event-triggered monolithic pixel detector with storage of multiple timestamps
in Journal of Instrumentation
Johnsen AJ
(2012)
A complete quantum mechanical study of chlorine photodissociation.
in The Journal of chemical physics
Karsili TN
(2014)
Symmetry matters: photodissociation dynamics of symmetrically versus asymmetrically substituted phenols.
in Physical chemistry chemical physics : PCCP
Kershis MD
(2013)
Exploring surface photoreaction dynamics using pixel imaging mass spectrometry (PImMS).
in The Journal of chemical physics
King GA
(2012)
Vibrational energy redistribution in catechol during ultraviolet photolysis.
in Physical chemistry chemical physics : PCCP
King GA
(2010)
Dynamical insights into (1)pi sigma(*) state mediated photodissociation of aniline.
in The Journal of chemical physics
King GA
(2009)
High resolution photofragment translational spectroscopy studies of the ultraviolet photolysis of phenol-d(5).
in The journal of physical chemistry. A
King GA
(2010)
Exploring the mechanisms of H atom loss in simple azoles: Ultraviolet photolysis of pyrazole and triazole.
in The Journal of chemical physics
Kirkbride J
(2014)
Polarization spectroscopy of a velocity-selected molecular sample.
in Optics letters
Kirkbride JM
(2013)
Coherent transient spectroscopy with continuous wave quantum cascade lasers.
in Physical chemistry chemical physics : PCCP
Kirkbride JM
(2014)
Pump and probe spectroscopy with continuous wave quantum cascade lasers.
in The Journal of chemical physics
Klos J
(2018)
Experimental and theoretical studies of the Xe-OH(A/X) quenching system.
in The Journal of chemical physics
Klos J
(2012)
Ab Initio studies of the interaction potential for the Xe-NO( X 2?) van der Waals complex: Bound states and fully quantum and quasi-classical scattering
in The Journal of Chemical Physics
Lam J
(2014)
Collisional trap losses of cold magnetically trapped Br atoms
in Physical Review A
Lehman JH
(2013)
Electronic quenching of OH A 2S+ induced by collisions with Kr atoms.
in The journal of physical chemistry. A
Lipciuc ML
(2017)
Photofragmentation dynamics of N,N-dimethylformamide following excitation at 193 nm.
in The Journal of chemical physics
Luk L
(2013)
Unraveling the role of protein dynamics in dihydrofolate reductase catalysis
in Proceedings of the National Academy of Sciences
Marchetti B
(2015)
Near ultraviolet photochemistry of 2-bromo- and 2-iodothiophene: Revealing photoinduced ring opening in the gas phase?
in The Journal of chemical physics
McCormack E
(2012)
Detection of electrons in the surface ionization of H Rydberg atoms and H 2 Rydberg molecules
in Journal of Physics B: Atomic, Molecular and Optical Physics
McCormack EA
(2012)
Population transfer and rapid passage effects in a low pressure gas using a continuous wave quantum cascade laser.
in The Journal of chemical physics
McCormack EA
(2010)
Level crossings in the ionization of H(2) Rydberg molecules at a metal surface.
in The journal of physical chemistry. A
Meyer K
(2015)
Ejection of Coulomb Crystals from a Linear Paul Ion Trap for Ion-Molecule Reaction Studies
in The Journal of Physical Chemistry A
Murdock D
(2015)
UV-induced isomerization dynamics of N-methyl-2-pyridone in solution.
in The journal of physical chemistry. A
Murdock D
(2012)
Photofragmentation Dynamics in Solution Probed by Transient IR Absorption Spectroscopy: ps*-Mediated Bond Cleavage in p-Methylthiophenol and p-Methylthioanisole.
in The journal of physical chemistry letters
Murdock D
(2012)
UV photodissociation dynamics of iodobenzene: Effects of fluorination
in The Journal of Chemical Physics
Murdock D
(2014)
Transient UV pump-IR probe investigation of heterocyclic ring-opening dynamics in the solution phase: the role played by ns* states in the photoinduced reactions of thiophenone and furanone.
in Physical chemistry chemical physics : PCCP
Nichols B
(2015)
Steric effects and quantum interference in the inelastic scattering of NO(X) + Ar.
in Chemical science
Nomerotski A
(2011)
Pixel imaging mass spectrometry with fast silicon detectors
in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Nomerotski A
(2010)
Pixel Imaging Mass Spectrometry with fast and intelligent Pixel detectors
in Journal of Instrumentation
Northern J
(2010)
Chirped quantum cascade laser induced rapid passage signatures in an optically thick gas
in Applied Physics B
Northern JH
(2010)
Rapid passage signals induced by chirped quantum cascade laser radiation: K state dependent-delay effects in the nu2 band of NH3.
in Optics letters
Oliver T
(2010)
The conformer resolved ultraviolet photodissociation of morpholine
in Chemical Science
Oliver TA
(2011)
Linking photochemistry in the gas and solution phase: S-H bond fission in p-methylthiophenol following UV photoexcitation.
in Faraday discussions
Oliver TA
(2015)
Exploring Autoionization and Photoinduced Proton-Coupled Electron Transfer Pathways of Phenol in Aqueous Solution.
in The journal of physical chemistry letters
Oliver TA
(2010)
The ultraviolet photodissociation of axial and equatorial conformers of 3-pyrroline.
in The Journal of chemical physics
Oliver TA
(2010)
Ultraviolet photodissociation dynamics of 2-methyl, 3-furanthiol: tuning pi-conjugation in sulfur substituted heterocycles.
in The journal of physical chemistry. A
Oliver TA
(2011)
Position matters: competing O-H and N-H photodissociation pathways in hydroxy- and methoxy-substituted indoles.
in Physical chemistry chemical physics : PCCP
Orr-Ewing AJ
(2017)
Taking the plunge: chemical reaction dynamics in liquids.
in Chemical Society reviews
Orr-Ewing AJ
(2015)
Dynamics of bimolecular reactions in solution.
in Annual review of physical chemistry
Orr-Ewing AJ
(2014)
Perspective: Bimolecular chemical reaction dynamics in liquids.
in The Journal of chemical physics
Orr-Ewing AJ
(2011)
Chemical Reaction Dynamics in Liquid Solutions.
in The journal of physical chemistry letters
Perkins T
(2015)
Surface-hopping trajectories for OH(A2S+) + Kr: Extension to the 1 A ? state
in The Journal of Chemical Physics
Pickering JD
(2016)
Communication: Three-fold covariance imaging of laser-induced Coulomb explosions.
in The Journal of chemical physics
Preston TJ
(2014)
Direct and indirect hydrogen abstraction in Cl + alkene reactions.
in The journal of physical chemistry. A
Remmert S
(2009)
Reduced Dimensionality Quantum Dynamics of CH 3 + CH 4 ? CH 4 + CH 3 : Symmetric Hydrogen Exchange on an Ab Initio Potential
in The Journal of Physical Chemistry A
| Description | This EPSRC Programme Grant involving 10 research groups from the Universities of Bristol and Oxford, is making significant advances in the fundamental study of mechanisms of chemical and photochemical reactions. The use of new technology to study such chemical processes is also leading to innovations in broader areas such as analytical science. Full details of the project are given at the website http://dynamics.chem.ox.ac.uk/ and a few key outcomes to date are summarized here. (1) Advances in mass spectrometry using novel imaging detectors that can provide both spatial and velocity information. (2) Breakthroughs in the study of chemical and photochemical processes occuring in solution in liquids using femtosecond laser based transient absoprtion methods and new theoretical methods for accurate simulation of reactions in liquids. (3) Use of velocity map imaging (and related) methods to observe collisional scattering and photodissociation mechanisms with quantum-state resolution, and to explore non-adiabatic dynamics at conical intersections between electronic states. (4) Advances in fundamental theory of chemical reactions, and of the theoretical treatment of bulk liquids. (5) Develpment and application of new methods to study collisions at ultra-low temperatures. The consortium has published more than 150 papers in international journals over the course of the grant. A representative selection of these papers is given here. |
| Exploitation Route | Advances in spatial and velocity map imaging led to the award of a Programme grant to the Bristol and Oxford groups to develop further these techniques and their applications (EP/L005913/1). Collaborations with SMEs Photek Ltd and SAI Ltd, as well as the PImMS consortium involving the Rutherford Appleton Laboratory and University of Oxford are advancing technical developments and applications of imaging techniques, including new methods for imaging mass spectrometry. Computational developments, for example in accurate simulation of reactions in solution, are being incorporated into major software packages for simulation of biomolecule dynamics such as CHARMM. |
| Sectors | Chemicals Creative Economy Education Energy Environment Healthcare Pharmaceuticals and Medical Biotechnology Other |
| URL | http://dynamics.chem.ox.ac.uk/ |
| Description | Developments in imaging mass spectrometry and in imaging methods are transferring to mass spectrometry manufacturers (e.g. Scientific Analysis Instruments Ltd)and manufacturers of scientific instrumentation for imaging (e.g. Photek Ltd, Photonis). The development of the Danceroom Spectroscopy project is having a substantial cultural and educational impact: see http://danceroom-spec.com/ for a list of activities. |
| First Year Of Impact | 2009 |
| Sector | Creative Economy,Education,Manufacturing, including Industrial Biotechology |
| Impact Types | Cultural Economic |
| Description | EPSRC Programme Grant |
| Amount | £4,663,077 (GBP) |
| Funding ID | EP/L005913/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 01/2014 |
| End | 09/2019 |
| Description | ERC Advanced Grant |
| Amount | € 2,666,684 (EUR) |
| Funding ID | 290966 |
| Organisation | European Research Council (ERC) |
| Sector | Public |
| Country | Belgium |
| Start | 02/2012 |
| End | 01/2017 |