My research seeks fundamental understanding the electron dynamics of the molecular bond. While this is a curiosity-driven pursuit, the applications are likely to follow, because molecular dynamics is the key mechanism in chemistry, biology and medicine.
This research direction crystallized in my mind over 20 years ago, when I was looking at fragmentation dynamics of molecular oxygen revealed in a new experimental technique we devised for synchrotron radiation studies at the Daresbury Laboratory. On a noisy map of electron-ion coincidences I could see quite clearly the nuclear motion of the molecule, but the electronic motion remained unresolved.
To probe the electrons we moved our experiments to the Rutherford Appleton Laboratory, where short, intense laser pulses were available. A new phenomenon was soon discovered, the multielectron dissociative ionisation, a new experimental technique of covariance mapping was developed to study it and a field-ionisation Coulomb-explosion model was proposed to describe it. With these developments, and indirect study of electron dynamics became possible. The existence of bond hardening was confirmed experimentally and counterintuitive alignment was explained in terms of electron oscillations in the molecular bond.
When laser-generated pulses of light were shortened to the attosecond timescale at the beginning of this century, a direct probing of the electron dynamics became possible. My initial work in this area started from elucidating and the key mechanisms of attosecond pulse generation such as synchronisation of high harmonics and progressed to controlling the attosecond emission. This research is a part of a larger, collaborative effort in developing attosecond technology.
Recent construction of powerful free-electron lasers has provided us with very intense x-ray pulses we use to probe the electron dynamics in inner shells of atoms and molecules. To reveal electron correlations the experimental technique has been extended to partial covariance mapping.
This research is summarised in my inaugural lecture "On the edge of quantum reality - probing molecules with intense laser fields".
Key: (P) = Principal Investigator, (C) = Co-Investigator
- EP/I032517/1 Attosecond Electron Dynamics in Molecular and Condensed Phase Systems (C) £5,838,510
- EP/C530772/1 Dynamic Imaging Of Matter At The Attosecond and Angstrom Scales (P) £200,882
- GR/S22424/01 Basic Technologies: Attosecond Technology - Light Sources, Metrology and Applications (P) £680,220
- GR/L12813/01 Manipulating The Dissociation Dynamics Of Simple Molecules In Intense Laser Fields (P) £147,947
- GR/J24683/01 Multielectron Dissociative Ionization - An Unexplained Phenomenon In Molecules In Intense Laser Fields (C) £144,963
- GR/G08217/01 The Coloumb Explosion Of Molecules In Intense Subpicosecond Laser Fields (C) £164,395
- GR/E91844/01 Covariance Mapping A Novel Time-Of-Flight Technique Applied To Multiphoton Ionisation (C) £63,982