Research
Malcolm H. Levitt
mhl@soton.ac.uk
We research on nuclear magnetic resonance (NMR) which is a powerful spectroscopic technique for examining the structure of matter, involving the use of a strong magnet and radio waves.
NMR allows us to examine the molecular structure of matter, determine how the molecules are arranged and how they are moving. In the form of magnetic resonance imaging (MRI), NMR allows the non-invasive determination of human anatomy and diagnosis of conditions such as cancer.
Our group researches on NMR methodology. We discover new ways to examine and understand the structure of matter, and we introduce new experiments and procedures into methods such as MRI and analytical NMR.
Our research is highly interdisciplinary, involving chemistry, biology, electromagnetism, quantum physics, cryogenic engineering and numerical computations. We have numerous international and UK collaborations, including the following groups:
- Richard and Lynda Brown (Southampton Chemistry): synthesis
- Richard Whitby (Southampton Chemistry): synthesis, physical chemistry and photochemistry
- Marcel Utz (Southampton Chemistry): electromagnetics and biochemistry
- Ilya Kuprov (Southampton Chemistry): theory and computations
- Marina Carravetta (Southampton Chemistry): solid-state NMR
- Joern Werner and Phil Williamson (Southampton Biochemistry): biochemistry
- Yifeng Yang (Southampton Engineering): cryogenics
- Hendrick Ulbricht (Southampton Physics): quantum physics
- John Morton (UCL Physics): electron magnetic resonance
- Tony Horsewill (Nottingham Physics): neutron scattering and cryogenic NMR
- Kevin Brindle (Cambridge Biochemistry): in vivo NMR and MRI
- Walter Köckenberger (Nottingham Physics): hyperpolarization
- Jan-Henrik Ardenkjaer-Larsen (Copenhagen, Denmark): hyperpolarization
- Toomas Rõõm (Tallinn, Estonia): infrared and THz spectroscopy
- Ivo Heinmaa (Tallinn, Estonia): cryogenic NMR
- Ron Lawler (Brown University, USA): photochemistry
- Rahim Rizi (Univ Pennsylvania Medical School, USA): hyperpolarization and in vivo NMR/MRI
- Koichi Komatsu and Yas Murata (Kyoto, Japan): synthesis
- Marco Geppi (Pisa, Italy): chemistry
Click the image to access details of my textbook Spin Dynamics (2nd edition, Wiley, 2007) and links to errata and comments.
Click the image to access my software SpinDynamica for general and powerful spin dynamical simulations in the symbolic and numerical environment of Mathematica.
Research
Nuclear singlet states
Our group demonstrated that in some circumstances, it is possible to exploit long-lived nuclear singlet states that have much longer lifetimes than ordinary nuclear magnetization. In some cases we demonstrated maintenance of nuclear spin order for over half-an-hour in a room-temperature liquid. Our group is currently combining long-lived singlet states with hyperpolarization technology, which can enhance NMR signals by many orders of magnitude, but which suffers from the limited lifetime of the effect. By generating hyperpolarized singlet states we hope to maintain the hyperpolarization for a long time, which could have benefits in many forms of NMR spectroscopy and MRI.
Molecular Quantum Rotors
Molecular rotors are systems with exceptionally high degrees of internal molecular mobility. The picture shows one of the systems we are studying: molecules of dihydrogen (H2) enclosed in a modified fullerene cavity. The dihydrogen molecules are completely free to rotate, even at cryogenic temperatures, and behave as quantum rotors. The physical properties of these systems are very interesting, since the spin and spatial degrees of freedom are entangled.
Magic-Angle Spinning
MAS improves the sensitivity and resolution of NMR spectra, but averages out dipole-dipole interactions which carry molecular structural information. We are developing recoupling methods which allow this information to be recovered under high-resolution conditions. Our main approach is symmetry-based recoupling. We are also developing and applying techniques for measuring J-couplings in solids, in the presence of MAS. We are applying these MAS techniques to rhodopsin, zeolites, and molecular rotors. We are also developing equipment for MAS at cryogenic temperatures.
C
ryogenic Magic-Angle-Spinning NMR
The aim of this project is to enhance the signal strength of solid-state nuclear magnetic resonance (NMR) by performing experiments on rapidly-rotating samples at cryogenic temperatures (approaching the boiling point of liquid helium).
By the end of the project, we expect to:
- develop hardware capable of spinning solid samples at temperatures down to 20 Kelvin and rotation frequencies in excess of 15 kHz, with a stability in excess of 5 Hz;
- develop chemical agents (“cryorelaxors”) capable of accelerating nuclear spin relaxation at cryogenic temperatures;
- perform cryoMAS NMR on isotopically-labelled biomolecules, in order to demonstrate the expected sensitivity enhancement by a factor of 10-20.
Membrane Proteins: Rhodopsin
Rhodopsin is a 7-helix transmembrane protein which is found in the eyes of higher organisms. It captures photons and transduces the optical impulse into a chemical signal. In collaboration with the groups of Johan Lugtenburg and Huub de Groot in Leiden, and Wim de Grip in Nijmegen, we have used solid state NMR to study the conformational changes of this molecule upon visual excitation.
The image shows the X-ray structure of rhodopsin (from K. Palczewski, et al., Science 289, 739-745 (2000)), showing the helices of the opsin protein and the 11-cis-retynilidene ligand that captures the light (space-filling model).
People
Dr. Javier Alonso-Valdesueiro
Post Doc Research interests:• RF Coils and Circuits in NMR/MRI
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Dr. Benno Meier
Post Doc Research interests:
• Hyperpolarization
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Dr. Gabriele Stevanato
Post Doc Research interests:
• Hyperpolarized long-lived states • Liquid state NMR methodology • Dissolution-DNP • Multispin systems theory • Numerical simulations
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Mike Jolly
PhD Student
• The development of cryogenic magic angle spinning NMR for biomolecular systems
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Research interests:Stuart Elliott
PhD Student
• Hyperpolarization
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Research interests:Dr. Karel Kouril
Post Doc Research interests:
• Solid State NMR• Endofullerenes • Cryogenic NMR Instrumentation
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Dr. Pär Håkansson
Post Doc
• MD and Quantum chemistry, Long-lived Nuclear spin state
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Research interests:Dr. Maria Concistrè
Post Doc
• Solid State NMR of bio-samples
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James Eills
Phd Student
Research interests:
• Long-Lived Nuclear Spin States • Hyperpolarization • Liquid Crystals • Parity Non-Conservation
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Dr. Giuseppe Pileio
Senior Research Fellow
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Homepage |
Publications |
g.pileio@soton.ac.uk |
Publications
Resources
Presentations
Malcolm Levitt’s conference presentations, seminars and tutorials.
pdf files are available at the links
2014
- iMR-CDT research conference, Dundee, Scotland, April 2014.
- Topic: Long-lived states and spin isomers. pdf
Personal
Malcolm Levitt’s personal website is here: www.malcolmhlevitt.com
Some of Malcolm’s music may be listened to here
The latest track “Hold Me Now” is here: