Positrons are the antimatter version of electrons and so their fate in a matter world is ultimately to annihilate. However, prior to this, a positron may combine with an electron to form a matter-antimatter hybrid called positronium. This is akin to a hydrogen atom with the proton replaced by a positron. Fundamental to our understanding of the physical universe, positron and positronium are these days also acknowledged as being fantastically useful in practical applications such as probing material properties and medical diagnostics. However, there is still much that we do not know for sure about the details of the interactions of these particles with ordinary matter. For example if, in a collision with an atom or molecule, a positron captures an electron, in which directions is the positronium likely to travel and with what probability? More...
Published: Jun 17, 2015 12:35:19 PM
How light of different colours is absorbed by carbon dioxide (CO2) can now be accurately predicted using new calculations developed by a UCL-led team of scientists. This will help climate scientists studying Earth’s greenhouse gas emissions to better interpret data collected from satellites and ground stations measuring CO2. More...
Published: Jun 15, 2015 10:29:10 AM
New research from UCL has uncovered additional second laws of thermodynamics which complement the ordinary second law of thermodynamics, one of the most fundamental laws of nature. These new second laws are generally not noticeable except on very small scales, at which point, they become increasingly important. More...
Published: Feb 10, 2015 11:55:53 AM
Dr Jonathan Underwood
Telephone: +44 (0) 20 7679 2564 (Internal 32564)
I was an undergraduate at the University of Nottingham where I gained a BSc(Hons) in Chemistry in 1995. I remained at Nottingham studying for a PhD under the supervision of Prof Ivan Powis from 1995 to 1999. The topic of my PhD work was Vector Properties in Molecular Photodissociation. Following a brief postdoctoral stint with Prof Katharine Reid at Nottingham I spent 3.5 years (from 2000 to 2003) as a visiting research fellow with Dr Albert Stolow at the Steacie Institute for Molecular Sciences, National Research Council Canada. While at the Steacie Institute I worked on the application of femtosecond laser techniques to the study and control of molecular photophysics. In 2003 I returned to the UK to take a lectureship in the Department of Physics and Astronomy at the Open University. In 2007 I transferred to a lectureship in the Department of Physics and Astronomy at University College London. My current position is co-funded by the Photon Science Department at the STFC Rutherford Appleton Laboratory, where I spend roughly half of my time.
My research interests are focussed on the use of femtosecond lasers for the study and control of molecular physics. My research is described in the AMOPP webpages about Ultrafast laser spectroscopy and Strong Laser Interactions and you can read more about my research here.
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