Queen's University Belfast 
School of Mathematics & Physics 
Applied Mathematics & Theoretical Physics 
Centre for Theoretical Atomic, Molecular and Optical Physics (CTAMOP)

Dr H W van der Hart
(Hugo van der Hart)

Contact Information
 Postal address
 Dr H W van der Hart
Dept of Applied Mathematics and Theoretical Physics
David Bates Building
Queen's University Belfast
Belfast, BT7 1NN
Northern Ireland
United Kingdom
 Telephone +44 (0)28 9097 6048 (direct line)
 Telephone +44 (0)28 9097 6001/2 (departmental office)
 Fax +44 (0)28 9097 6061
 email h.vanderhart@qub.ac.uk
 Official homepage

Within Queen's University
 Position
 Location
 Room 0G.031, David Bates Building
 Telephone (internal) 6048

Research Interests
The Rmatrix Floquet approach for multiphoton processes
My main interest is the theoretical study of manyelectron systems embedded in
strong laser fields. One of the techniques used at present is
the RmatrixFloquet approach . This approach has been
developed during the 1990's and is one of the leading methods for the
investigation of multiphoton processes. Recent highlights of applications of
RmatrixFloquet theory include
 Excellent agreement with fully independent timedependent calculations
for ionization rates of He at 390 nm. Agreement is typically within 10% for
a process requiring absorption of at least 9 photons.
 Twophoton double ionization of He for photon energies between 40 and 48
eV. Rmatrix Floquet theory was a pioneering technique for this process,
which is now a focal point for theoretical and experimental investigation.
 Twophoton emission of innershell electrons when complex atoms are
irradiated by VUV (freeelectron) laser light. We have studied emission of a 1s
electron from Li^{}. We have also established that emission of a 2s electron
from Ne^{+} in the 1s^{2}2s^{2}2p^{5} ground state is
a very important twophoton ionization process.
Timedependent Rmatrix approach The RmatrixFloquet approach
can not be used to describe the response of atoms to ultrashort light fields,
since it assumes the pulse to be infinitely long. We are therefore developing a
timedependent Rmatrix approach. The first application of this technique was to
study Ar atoms in intense fewcycle pulses. From the behaviour of the
wavefunction, we were able to obtain ionization in excellent agreement with
those obtained using the RmatrixFloquet approach, thereby demonstrating the
accuracy of this new technique.
Recollision model calculations A different approach to investigating the behaviour of atoms in strong laser fields is
through the application of model calculations. These calculations cannot provide
detailed results, but they provide insight into the physics of manyelectron atoms in
strong laser fields.
Bspline basis set techniques
I am also highly interested in the development and application of Bspline techniques
for atomic physics calculations. Bspline basis sets are very well suited for
highaccuracy calculations. These sophisticated basis sets have been applied to study
the following properties of two and threeelectron atoms :
 Energies
 Radiative lifetimes
 Autoionization lifetimes
 Electron scattering
 Photoionization
 Double photoionization
 Triple photoionization
For an overview of research publications, please visit my official homepage.

Teaching
 Undergraduate courses:
 Ph.D. students
