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
Abou-Chahine F
(2013)
Photoisomerization and photoinduced reactions in liquid CCl4 and CHCl3.
in The journal of physical chemistry. A
Abou-Chahine F
(2013)
Vibrationally resolved dynamics of the reaction of Cl atoms with 2,3-dimethylbut-2-ene in chlorinated solvents
in Chem. Sci.
Allum F
(2018)
Coulomb explosion imaging of CH3I and CH2ClI photodissociation dynamics
in The Journal of Chemical Physics
Amini K
(2017)
Alignment, orientation, and Coulomb explosion of difluoroiodobenzene studied with the pixel imaging mass spectrometry (PImMS) camera.
in The Journal of chemical physics
Amini K
(2018)
Photodissociation of aligned CH3I and C6H3F2I molecules probed with time-resolved Coulomb explosion imaging by site-selective extreme ultraviolet ionization.
in Structural dynamics (Melville, N.Y.)
Amini K
(2015)
Three-dimensional imaging of carbonyl sulfide and ethyl iodide photodissociation using the pixel imaging mass spectrometry camera.
in The Review of scientific instruments
Aoiz FJ
(2015)
A new perspective: imaging the stereochemistry of molecular collisions.
in Physical chemistry chemical physics : PCCP
Aoiz FJ
(2009)
Inelastic scattering of He atoms and NO(X2Pi) molecules: the role of parity on the differential cross section.
in The journal of physical chemistry. A
Aoiz FJ
(2009)
The collisional depolarization of (2S+1)Sigma radicals by closed shell atoms: Theory and application to OH(A (2)Sigma(+))+Ar.
in The Journal of chemical physics
Banks ST
(2009)
Chemical reaction surface vibrational frequencies evaluated in curvilinear internal coordinates: Application to H + CH(4) <==> H(2) + CH(3).
in The Journal of chemical physics
Banks ST
(2009)
An improved treatment of spectator mode vibrations in reduced dimensional quantum dynamics: application to the hydrogen abstraction reactions mu + CH4, H + CH4, D + CH4, and CH3 + CH4.
in The Journal of chemical physics
Bell M
(2009)
Ultracold molecules and ultracold chemistry
in Molecular Physics
Bell MT
(2009)
Ion-molecule chemistry at very low temperatures: cold chemical reactions between Coulomb-crystallized ions and velocity-selected neutral molecules.
in Faraday discussions
Brauße F
(2018)
Time-resolved inner-shell photoelectron spectroscopy: From a bound molecule to an isolated atom
in Physical Review A
Brouard M
(2012)
The ultraviolet photodissociation of CS2: the S(1D2) channel.
in The Journal of chemical physics
Brouard M
(2014)
Fully quantum state-resolved inelastic scattering of NO(X) + Kr: differential cross sections and product rotational alignment.
in The Journal of chemical physics
Brouard M
(2013)
Rotational alignment effects in NO(X) + Ar inelastic collisions: an experimental study.
in The Journal of chemical physics
Brouard M
(2009)
Collisional depolarization of NO(A) by He and Ar studied by quantum beat spectroscopy
in The Journal of Chemical Physics
Brouard M
(2013)
The fully quantum state-resolved inelastic scattering of NO(X) + Ne: experiment and theory
in Molecular Physics
Brouard M
(2011)
Application of fast sensors to microscope mode spatial imaging mass spectrometry
in Journal of Instrumentation
Brouard M
(2011)
The k-j-j' vector correlation in inelastic and reactive scattering.
in The Journal of chemical physics
Brouard M
(2011)
Collisional angular momentum depolarization of OH(A) and NO(A) by Ar: a comparison of mechanisms.
in The Journal of chemical physics
Brouard M
(2013)
Rotational alignment effects in NO(X) + Ar inelastic collisions: a theoretical study.
in The Journal of chemical physics
Brouard M
(2009)
Collisional depolarization of OH(A) with Ar: Experiment and theory.
in The Journal of chemical physics
Brouard M
(2012)
The application of the fast, multi-hit, pixel imaging mass spectrometry sensor to spatial imaging mass spectrometry.
in The Review of scientific instruments
Brouard M
(2012)
The hyperfine structure of NO(A2S+)
in Journal of Molecular Spectroscopy
Brouard M
(2013)
Origin of Collision-Induced Molecular Orientation
in Physical Review Letters
Bull J
(2013)
Electron-impact-ionization dynamics of five C 2 to C 4 perfluorocarbons
in Physical Review A
Bull J
(2015)
Electron ionization dynamics of N 2 and O 2 molecules: Velocity-map imaging
in Physical Review A
Bull J
(2017)
Electron-impact-ionization dynamics of S F 6
in Physical Review A
Bull JN
(2012)
Absolute total electron impact ionization cross-sections for many-atom organic and halocarbon species.
in The journal of physical chemistry. A
Bull JN
(2013)
Quantification of ions with identical mass-to-charge (m/z) ratios by velocity-map imaging mass spectrometry.
in Physical chemistry chemical physics : PCCP
Bull JN
(2014)
An introduction to velocity-map imaging mass spectrometry (VMImMS).
in European journal of mass spectrometry (Chichester, England)
Bull JN
(2014)
Absolute electron total ionization cross-sections: molecular analogues of DNA and RNA nucleobase and sugar constituents.
in Physical chemistry chemical physics : PCCP
Burgos Paci MA
(2013)
Products of the quenching of NO A 2S+ (v = 0) by N2O and CO2.
in Physical chemistry chemical physics : PCCP
Burt M
(2017)
Coulomb-explosion imaging of concurrent CH 2 BrI photodissociation dynamics
in Physical Review A
Campbell EK
(2012)
The vibrationally mediated photodissociation of Cl2.
in The Journal of chemical physics
Campbell EK
(2012)
Electronic polarization effects in the photodissociation of Cl2.
in The Journal of chemical physics
Chadwick H
(2014)
Collisional depolarisation in electronically excited radicals
in International Reviews in Physical Chemistry
Chadwick H
(2012)
A new potential energy surface for OH(A 2S+)-Kr: the van der Waals complex and inelastic scattering.
in The Journal of chemical physics
Chadwick H
(2014)
The collisional depolarization of OH(A (2)S(+)) and NO(A (2)S(+)) with Kr.
in The Journal of chemical physics
Chadwick H
(2014)
Inelastic Scattering of NO by Kr: Rotational Polarization over a Rainbow.
in The journal of physical chemistry letters
Chang YP
(2011)
Molecular photofragment orientation in the photodissociation of H2O2 at 193 nm and 248 nm.
in Physical chemistry chemical physics : PCCP
Chestakov D
(2010)
Angular distributions and angular momentum alignment of O(3PJ) atoms formed in the photolysis of O2via the Herzberg continuum
in Physical Chemistry Chemical Physics
Clark AT
(2012)
Multimass velocity-map imaging with the Pixel Imaging Mass Spectrometry (PImMS) sensor: an ultra-fast event-triggered camera for particle imaging.
in The journal of physical chemistry. A
Costen M
(2009)
Elastic Depolarization of OH(A) by He and Ar: A Comparative Study
in The Journal of Physical Chemistry A
Deb N
(2014)
Laser induced rovibrational cooling of the linear polyatomic ion C2H2(+).
in The Journal of chemical physics
Deb N
(2015)
Coulomb crystal mass spectrometry in a digital ion trap
in Physical Review A
Dixon RN
(2011)
Tunnelling under a conical intersection: application to the product vibrational state distributions in the UV photodissociation of phenols.
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 |