Anthony MeijerProf Anthony J. H. M. Meijer

Professor of Theoretical Chemistry

Room: G8a

Tel: +44-(0)114-22-29482

Fax: +44-(0)114-22-29346

email:

 


Biographical Sketch

Dr. Anthony J. H. M. Meijer graduated "Cum Laude" with an MSc in Chemistry from the University of Utrecht in the Netherlands in 1991. He then obtained a PhD in Natural Sciences from the University of Nijmegen in 1996. After the award of his PhD he spent 1996-1998 as a postdoctoral researcher at the Wayne State University in Detroit in the group of Prof. Evelyn Goldfield and 1999-2003 at University College London in the group of Prof. David Clary, FRS. He moved to the University of Sheffield in 2003 as a lecturer. He was promoted to senior lecturer in 2010 and to reader in 2014. He became professor of Theoretical Chemistry in 2018.

Professional Qualifications & Memberships

FRSC, FRAS

Teaching Qualifications

Certificate in Academic Practice (2006)

Research Keywords

Quantum Dynamics; Reactive Scattering; Chemical Reaction Dynamics; High-Performance Computing

Teaching Keywords

Physical and Theoretical Chemistry; Astrochemistry

Selected Publications:

Research Interests

Our research focuses on the theoretical/computational study of chemical reactions. The systems studied vary from small fundamental gas-phase reactions via gas-surface reactions to reactions involving flexible molecules. The results of these calculations are used together with the results of sophisticated experiments to obtain insight into the fundamentals of the reactions involved and to get a fundamental understanding of reaction dynamics. Below are given some projects to illustrate the work.

Vibrational control in transition metal complexes

Controlling the outcome of chemical reactions is arguably one of the holy grails of chemical physics. Recent experiments in the Weinstein group show that it is possible to direct a photophysical process using infrared light, taking a step towards achieving this goal. We are investigating the origins of this effect with a view of predicting the ability to control the outcome of experiments, done in the Weinstein group. Our focus lies on the development of potential energy surfaces for the systems under consideration which are then used in MCTDH calculations to simulate the dynamics of the processes.

Gas-surface scattering

We are currently working on the formation of H2 and other small molecules on graphite. H2 is the most abundant molecule in interstellar space and it plays an important role in the formation of stars and in interstellar chemistry through reactions with ions and radicals. Moreover, the energetics of the reaction directly influences the thermal balance of the interstellar medium. We are currently extending these methods to the formation of Complex Organic Molecules in the ISM in collaboration with Prof. Wendy Brown of Sussex University.

Gas-phase reactions

We have done extensive work on the H + O2 combustion reaction in the past, in particular focusing on the role the total angular momentum in this reaction. This lead to the first-ever rigorous theoretical cross sections, which compared well with experimental data from the Wolfrum group at the University of Heidelberg.

IRMPD Spectrum Theory vs. ExperimentWe are also currently applying the methods developed to the photo-dissociation of molecules inside van der Waals complexes, such as Ar-H2S and Ar-H2O, where angular momentum effects allow the van der Waals molecule to survive when one of its constituent molecules, such as H2S, is dissociated. We also have plans to apply the developed methods to the calculation of rates for reactions between radicals at low temperatures, which is important for our understanding of the interstellar medium and our understanding of extraterrestial planets and moons.

Reactions and Structure of conformationally flexible molecules

As molecules become larger, they generally become more flexible. As a consequence the potential energy surface becomes more complicated with many local minima, which may or may not be accessible at thermal energies. Each of these minima will be a distinct structure with e.g. a distinct IR spectrum. We are currently working on methods to allow us to generate many minima, which can then be screened for further investigation. This work ties into a number of collaborations we have, such as with Dr. Mathias Schäffer of the University of Cologne, who studies conformationally flexible molecules in the gas-phase using IRMPD spectroscopy as well as internal collaborations on the structure, reactivity, and properties of organic and organometallic compounds. This work is currently investigating hydrogen tunnelling at elevated temperatures in the gas phase.

Algorithm development for Quantum Dynamics Calculations

Quantum Dynamics calculations are significantly harder than standard electronic structure calculations due e.g. the exponential scaling with respect to the basis set size. We are working on methods that will allow us to solve the time-dependent Schrödinger equation more quickly. In particular, we develop efficient parallel methods to make calculations tractable.

Complete List of Publications

Teaching Section

Physical Chemistry

Undergraduate Courses Taught

  • Changes of state (Year 2)
    This segment combines first and second laws of thermodynamics learned in Level 1, so that you can use the Gibbs energy to discuss chemical systems, and the effects of external changes, such as temperature and pressure. This formalism is used to describe physical transformations of pure substances and how such phase changes change due to alteration in the external conditions.
  • Quantum Chemistry (Year 2)
    This course covers the basic principles of quantum chemistry with an emphasis on the application of quantum mechanical principles to the electronic structure of molecules.
  • Statistical Thermodynamics (Year 3)
    This segment introduces the statistical basis of thermodynamics through development of the concept of the partition function and using it to derive certain properties of ideal monatomic and diatomic gases. It relates both quantum mechanics and spectroscopy to thermodynamic aspects of molecular behaviour. The chief goal of the segment is to establish means whereby Third Law entropies may be calculated and the point of equilibrium established in simple chemical reactions.
  • Chemistry in Space (Year 4)
    This course expands on level 3 courses in Physical Chemistry and apply concepts learned therein to the chemistry of compounds in space in general and the interstellar medium in particular.

Tutorial & Workshop Support

  • First Year General Tutorials.
  • Second Year Physical Chemistry Tutorials.
  • Third Year Workshops (Statistical Thermodynamics).
  • Third Year Literature Review.
  • Fourth Year Workshops (Chemistry in Space).

Laboratory Teaching

  • Third Year Advanced Physical Chemistry
  • Fourth Year Research Project

Journal articles

Chapters

  • Goldfield EM & Meijer AJHM (2010) Scattering Theory: Predicting the outcome of Chemical Events In Brouard M & Vallance C (Ed.), Tutorials in Molecular Reaction Dynamics (pp. 49-87). Cambridge: RSC Publishing. RIS download Bibtex download
  • Meijer AJHM (2001) Time-dependent reactive scattering calculations using parallel computers In Althorpe SC, Soldán P & Balint-Kurti GG (Ed.), Time-dependent quantum dynamics (pp. 42-46). RIS download Bibtex download
  • Williams DA, Williams DE, Clary DC, Farebrother A, Fisher AJ, Gingell J, Jackman R, Mason N, Meijer AJHM, Perry J, Price S & Rawlings J (2000) The energetics and efficiency of H2 formation on surfaces of interstellar grain mimics In Combes F & Forêts GPD (Ed.), Molecular Hydrogen in Space (pp. 99-106). Cambridge University Press RIS download Bibtex download

Conference proceedings papers

  • Delor M, Scattergood PA, Sazanovich IV, Keane T, Greetham GM, Meijer AJHM, Towrie M, Parker AW & Weinstein JA (2015) Controlling electron transfer in condensed phase with bond-specific infrared excitation. Proceedings of SPIE - The International Society for Optical Engineering, Vol. 9549 RIS download Bibtex download
  • Patmore NJ, Meijer AJHM & Wilkinson LA (2014) Effects of electronic structure changes on stabilisation of the mixed-valence state in hydrogen bonded "dimers of dimers". ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol. 248 RIS download Bibtex download
  • Weinstein JA, Sazanovich IV, Delor M, Scattergood PA, Meijer AJHM, Portius P, Greetham G, Parker AW & Towrie M (2013) Ultrafast photoinduced charge-separation in molecular systems: Time-resolved IR, transient 2DIR, and controlling the rates and the pathways by vibrational perturbation. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol. 245 RIS download Bibtex download
  • Williams DA, Williams DE, Clary D, Farebrother A, Fisher A, Gingell J, Jackman R, Mason N, Meijer A, Perry J, Price S & Rawlings J (2000) The energetics and efficiency of H-2 formation on the surface of simulated interstellar grains. MOLECULAR HYDROGEN IN SPACE (pp 99-106) RIS download Bibtex download