Determining molecular chirality with femtosecond LASERs

As chiral enantiomers share almost all physical properties they are only distinguishable through interaction with another chiral system, be it chiral molecules or circularly polarised light. Differences in the real and imaginary parts of the refractive index between right and left circularly polarised light are very small, around 0.01%.

The result is conventional circular dichroism effects are slow and insensitive, producing asymmetries on the order of 0.1%. <br><br>However the PhotoElectron Circular Dichroism effect first measured in 2001 exhibits a large asymmetry in the photoelectron angular distribution on the order of 10%. By coupling this PECD effect with multiphoton ionisation using femtosceond LASERs, it is possible to study the ultrafast dynamics of these chiral molecules.<br><br> In this thesis I present a simple device created at QUB that is capable of measuring the PECD effect using stereo-electron detection to directly measure the forward and backward emitted electrons.