Attosecond Electron Dynamics in Molecular and Condensed Phase Systems

Lead Research Organisation: Imperial College London
Department Name: Physics


This is a programme of advanced research with potential for extremely high scientific impact and applications to areas of great strategic importance to the UK, such as renewable energy and biomolecular technology. The aim is to develop and apply a combination of cutting-edge experimental and theoretical tools to observe and model dynamics in molecules and condensed phase matter with 100 attosecond temporal and nanometre spatial resolutions. The temporal resolution we will achieve is two orders of magnitude beyond the current state-of-the-art for measurements in larger molecules and condensed matter. The history of science shows that whenever such large improvements in measurement capability occur major new breakthroughs are inevitable. For instance, it has recently emerged that sudden electronic excitation in key molecular building blocks of matter is followed by a universal primary event - sub-femtosecond to few femtosecond migration of electric charge across nanometres. This charge migration, expected to be extremely important in triggering subsequent nuclear dynamics and so controlling chemical change, is too fast to be observed with existing methods. The proposed research programme will apply the world-leading experimental and theoretical tools developed by the assembled team to study the nature of charge migration and other previously unexplored attosecond-scale processes. We will pioneer the investigation in both condensed phase matter and large molecules including the building blocks of biomolecules. The knowledge gained from this research will lead to a new understanding of the first moments in the electronic excitation of matter and ultimately to, for example, new approaches for optimising artificial light harvesting, molecular electronic devices and biomolecular analysis.Imaging and controlling dynamics of matter at the level of electrons, especially far from equilibrium, and understanding the role of quantum coherence in molecules and nanoscale assemblies have been identified by the US Department of Energy as key components of five grand scientific challenges to basic energy sciences (Phys.Today, July 2008, p28-33). Our programme will enable the concerted effort and close linking of experiment and theory needed to address these questions. The UK has a unique opportunity for world leadership in this area, as we have assembled an exceptional team that commands all of the technical and theoretical tools required to lead this new and important area of science.Our programme will exploit two new types of measurements that we have already begun to develop: high harmonic generation (HHG) spectroscopy and attosecond pump-probe spectroscopy, and will apply them to the measurement of attosecond electron dynamics in large molecules and the condensed phase. This is a formidable challenge that will open new frontiers both experimentally and theoretically. This challenge will be met by our coordinated and balanced programme that will bring together theoretical and experimental expertise in attosecond physics, quantum chemistry, molecular structure and dynamics, ultrafast and intense-field science, nanoscale and plasma physics.The programme is structured into 4 interlinked projects, each of which makes a major contribution to the eventual research outcomes: Project 1: High harmonic generation (HHG) spectroscopy Project 2: Attosecond pump-probe spectroscopy Project 3: Coupling of charge migration and nuclear dynamics Project 4: Probing attosecond dynamics in the condensed phase .

Planned Impact

While the immediate beneficiaries of this knowledge will be academic our focus is on questions identified as key for the development of basic energy sciences over the next decades. Thus, in the intermediate term, we expect impact in a number of industrial sectors, such as renewable energy, nanotechnology devices and pharmaceuticals. The exploitable knowledge that can be forseen includes: - Characterization of the initial electronic steps in light harvesting that can be exploited to aid engineering of more efficient solar cells - Identification of the full mechanism behind the use of intense laser field scalpels as a biomolecular analysis tool with the resultant increase of fidelity and throughput - Insights into few fs electron dynamics in nanoscale objects with the possibility to develop ultrafast nanophotonic and nanoplasmonic devices for communications and information processing Aside from economic benefits there are obvious societal benefits arising from these potential outcomes (e.g. clean and efficient energy sources, medical advances). The second most important channel of economic impact (after the knowledge generated) will be the direct exploitation of the new instrumentation and software developed through this research. This instrumentation will offer advanced measurement tools that will find application across a wide range of scientific and technical activities. The categories of new instrumentation are for example: - Compact and robust short pulse light sources (applications to e.g. biomedical research, metrology) - Ultrafast optical devices and diagnostics (applications to e.g. multiple ultrafast laser technologies) - XUV absorption workstation for ultrafast measurements in a wide range of condensed samples (applications e.g. to catalysis) - Nanoscale droplet and liquid jet delivery systems (applications to e.g. biological imaging at FELs, fusion technology) - New software tools e.g. compatible with future Gaussian releases (applications to e.g. quantum chemistry) The training resulting from the programme will be of benefit to a number of staff funded directly by the programme (we anticipate > 10 individuals to be employed as PDRA's and PG's during the course of the work) and from other sources (> 10 other PG's from UK, EU and other sources) in the course of the Programme. The important skills that will be imparted are: - Ultrafast science and measurement methods - Complex quantum simulations - Advanced data analysis techniques These are highly valued skills across a broad suite of employers e.g. AWE, financial modelling, the opto-electronics and laser industries, biochemical analysis and instrumentation manufacturers, telecommunications and defence. The topic of this research - making the fastest ever measurements - is an ideal subject for the broad engagement with the public. We have found a considerable appetite for our popular presentations in the media and at the 2008 Royal Society Summer Exhibition. We believe this is an ideal area to capture public interest in science as it is at the forefront of measurement and knowledge. It is an excellent opportunity to communicate the importance and fascination of physics to a broad public, especially since mainstream physics is typically harder to sell than astronomy or particle physics where the public is much better prepared.


10 25 50
Description Summary of Key Outputs
• Generation and characterisation of sub-1.5 cycle CEP stable pulses at 800nm and 1800nm*
• Understanding the role of different substituents in HHG from substituted benzenes
• Theoretical proof-of-concept of measuring molecular hole dynamics with XIHHG
• Development of a soft X-ray isolated sub-femtosecond pulse source in the photon energy range 100- > 500 eV*
• Demonstration of XANES spectroscopy with this source in P3HT polymer films*
• Multi-colour field driven HHG to control electron trajectory in time and space
• Development of new two-field approaches to electric field retrieval
• Generation of perfectly synchronised attosecond pulse pairs at 20eV and 90eV*
• Temporally characterising attosecond photoelectron wavepackets from a surface*
• Theoretical proof-of-concept demonstration of measuring charge migration using spLEAD
• Discovery and characterisation of new intra- and inter-atomic inner-shell phenomena
• First X-ray pump-probe studies with sub-10 fs pulses at an X-ray FEL
• Demonstration of liquid sheet jets of ~1 micron thickness fabricated using 2-photon laser printing*
• Discovery of the fundamental importance of the initial nuclear quantum state in charge migration*
• Advances in handling the calculation of coupled electronic-nuclear dynamics*
We have indicated with a * those outputs that form the basis for the capabilities that are exploited in follow up grants and proposals.
2 dimensional mass spectrometry developed.
Exploitation Route We are further developing new measurement concepts such as attosecond transient absorption, HHG spectroscopy, attosecond pump-probe fragmentation studies and Auger based detection methods for tracking ultrafast electron hole dynamics. 2D mass spectrometry concept was patented.
Sectors Aerospace

Defence and Marine


Digital/Communication/Information Technologies (including Software)




including Industrial Biotechology

Pharmaceuticals and Medical Biotechnology

Description Development of compact X-ray analytical techniques applicable to a wide range of materials including biomaterials. This has been further pursued in collaboration with LCLS, SLAC, Stanford, USA and first investigations of isopropanol and glycine obtained (former now published). Furthermore the work has been instrumental in developing the objectives of the Attosecond Campaign coordinated by SLAC, an international collaboration of which we are a key part, to develop attosecond timescale measurements of ultrafast electron dynamics. Development of new types of liquid sheet jet with micron scale thickness with potential for analytical measurements in chemical and biotechnology sector. Development of 2-dimensional mass spectrometry via partial covariance analysis. Out patent on this topic has attracted the interest of US and UK start-ups interested in licensing the technology - discussions are ingoing.
First Year Of Impact 2022
Sector Chemicals,Energy,Pharmaceuticals and Medical Biotechnology,Other
Impact Types Cultural



Description EPSRC Standard Grant
Amount £1,200,000 (GBP)
Funding ID EP/R019509/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 05/2018 
End 05/2022
Title HHG based X-ray spectroscopy 
Description Development of sub-femtosecond coherent X-ray source based on HHG into the soft X-ray range (100 - 550 eV). First demonstration of recording static XANES in a polymer sample at the S L and C K edges, being developed as a time resolved technique. 
Type Of Material Improvements to research infrastructure 
Year Produced 2016 
Provided To Others? Yes  
Impact Too soon to tell - but very promising. 
Description Bucksbaum Group - Stanford University 
Organisation Stanford University
Country United States 
Sector Academic/University 
PI Contribution We have provided ideas and expertise to progress research in ultrafast X-ray science by leading and participating in a number of joint beamtimes.
Collaborator Contribution Through this collaboration we have been able to efficiently engage in X-ray free electron laser research at the LCLS facility SLAC through their local resources and manpower. It has enabled around 10 separate beam-times.
Impact A number of research papers including 1 PRL, 2 Nature Communications and more in preparation.
Start Year 2011
Description MBI Berlin 
Organisation Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy; Research Network Berlin
Country Germany 
Sector Academic/University 
PI Contribution An enduring collaboration was established through the subsequent transfer of one of the academics supported by the grant (Prof Mikhail Ivanov) to the Max Born Institute. We continue to work on experiments on topics of mutual interest providing benchmark data for their calculations.
Collaborator Contribution Multiple examples of supporting calculations from their large team of computational and theoretical physicists that has aided in interpretation of our experiments.
Impact Multiple joint publications
Start Year 2011