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
Doherty WG
(2011)
Production of cold bromine atoms at zero mean velocity by photodissociation.
in Physical chemistry chemical physics : PCCP
Duggan L
(2010)
PFI-ZEKE photoelectron and high resolution photoionization spectra of ND 3 with MQDT simulations
in Molecular Physics
Dulitz K
(2016)
Velocity-selected magnetic guiding of Zeeman-decelerated hydrogen atoms
in The European Physical Journal D
Dulitz K
(2015)
Zeeman deceleration of electron-impact-excited metastable helium atoms
in New Journal of Physics
Dulitz K
(2015)
Model for the overall phase-space acceptance in a Zeeman decelerator
in Physical Review A
Dulitz K
(2014)
Getting a Grip on the Transverse Motion in a Zeeman Decelerator
Dulitz K
(2014)
Getting a grip on the transverse motion in a Zeeman decelerator.
in The Journal of chemical physics
Dulitz K
(2016)
Zeeman deceleration of metastable nitrogen atoms
in Journal of Physics B: Atomic, Molecular and Optical Physics
Dunning G
(2015)
Vibrational relaxation and microsolvation of DF after F-atom reactions in polar solvents
in Science
Dunning GT
(2014)
Dynamics of photodissociation of XeF2 in organic solvents.
in Physical chemistry chemical physics : PCCP
Eyles CJ
(2012)
The effect of parity conservation on the spin-orbit conserving and spin-orbit changing differential cross sections for the inelastic scattering of NO(X) by Ar.
in Physical chemistry chemical physics : PCCP
Eyles CJ
(2011)
Interference structures in the differential cross-sections for inelastic scattering of NO by Ar.
in Nature chemistry
Eyles CJ
(2012)
Fully ?-doublet resolved state-to-state differential cross-sections for the inelastic scattering of NO(X) with Ar.
in Physical chemistry chemical physics : PCCP
Few J
(2014)
Rate constants for collisional quenching of NO (A(2)S(+), v = 0) by He, Ne, Ar, Kr, and Xe, and infrared emission accompanying rare gas and impurity quenching.
in Physical chemistry chemical physics : PCCP
Few J
(2017)
An FTIR emission study of the products of NO A2S+ (v = 0, 1) + O2 collisions.
in Physical chemistry chemical physics : PCCP
Frederix PW
(2009)
Photodissociation imaging of diatomic sulfur (S2).
in The journal of physical chemistry. A
Gardiner SH
(2014)
Fragmentation dynamics of the ethyl bromide and ethyl iodide cations: a velocity-map imaging study.
in Physical chemistry chemical physics : PCCP
Gardiner SH
(2015)
Gas-Phase Retro-Diels-Alder Reactions of Cyclohexene, 1-Methylcyclohexene, and 4-Methylcyclohexene following Photoexcitation at 193 nm: A Velocity-Map Imaging Study.
in The journal of physical chemistry. A
Gardiner SH
(2015)
Dynamics of the A-band ultraviolet photodissociation of methyl iodide and ethyl iodide via velocity-map imaging with 'universal' detection.
in Physical chemistry chemical physics : PCCP
Gilchrist AJ
(2013)
Predissociation dynamics of the C 3?g Rydberg state of molecular oxygen.
in The Journal of chemical physics
Gingell AD
(2010)
Cold chemistry with electronically excited Ca+ Coulomb crystals.
in The Journal of chemical physics
Glowacki DR
(2012)
Taking Ockham's razor to enzyme dynamics and catalysis.
in Nature chemistry
Glowacki DR
(2011)
Product energy deposition of CN + alkane H abstraction reactions in gas and solution phases.
in The Journal of chemical physics
Glowacki DR
(2011)
Ultrafast energy flow in the wake of solution-phase bimolecular reactions.
in Nature chemistry
Glowacki DR
(2010)
Alkene hydroboration: hot intermediates that react while they are cooling.
in Journal of the American Chemical Society
Glowacki DR
(2017)
Reaction and relaxation at surface hotspots: using molecular dynamics and the energy-grained master equation to describe diamond etching.
in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences
Glowacki DR
(2015)
Non-equilibrium reaction and relaxation dynamics in a strongly interacting explicit solvent: F + CD3CN treated with a parallel multi-state EVB model.
in The Journal of chemical physics
Greaves SJ
(2011)
Quasi-classical trajectory study of the dynamics of the Cl + CH4? HCl + CH3 reaction.
in Physical chemistry chemical physics : PCCP
Greaves SJ
(2010)
Velocity map imaging of the dynamics of bimolecular chemical reactions.
in Physical chemistry chemical physics : PCCP
Greaves SJ
(2011)
Vibrationally quantum-state-specific reaction dynamics of H atom abstraction by CN radical in solution.
in Science (New York, N.Y.)
Greetham GM
(2013)
Waveguide-enhanced 2D-IR spectroscopy in the gas phase.
in Optics letters
Grubb MP
(2014)
KOALA: a program for the processing and decomposition of transient spectra.
in The Review of scientific instruments
Guo A
(2018)
Mass-resolved ion microscope imaging over expanded mass ranges using double-field post-extraction differential acceleration
in International Journal of Mass Spectrometry
Halford E
(2014)
Modifications to a commercially available linear mass spectrometer for mass-resolved microscopy with the pixel imaging mass spectrometry (PImMS) camera.
in Rapid communications in mass spectrometry : RCM
Hancock G
(2010)
Frequency modulated circular dichroism spectroscopy: application to ICN photolysis
in Molecular Physics
Hancock G
(2013)
Vector correlations in the O 2 (a 1 ? g , v = 1) fragment formed in the 265 nm photodissociation of ozone
in Molecular Physics
Hancock G
(2009)
Diode laser based studies of the UV photolysis of molecular iodine.
in Physical chemistry chemical physics : PCCP
Hancock G
(2010)
Applications of midinfrared quantum cascade lasers to spectroscopy
in Optical Engineering
Harris S
(2014)
Transient electronic and vibrational absorption studies of the photo-Claisen and photo-Fries rearrangements
in Chem. Sci.
Harris SJ
(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
(2010)
Exploring the mechanisms of H atom loss in simple azoles: Ultraviolet photolysis of pyrazole and triazole.
in The Journal of chemical physics
King GA
(2010)
Dynamical insights into (1)pi sigma(*) state mediated photodissociation of aniline.
in The Journal of chemical physics
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 |