This document summarizes the career and research of Robert A. Jackson, who has over 37 years of experience modeling defects in materials. It outlines the key projects he has worked on, including early work modeling molecular crystals and fission gas in UO2 fuel. More recent work includes modeling zeolites, ferroelectric materials, molecular ionic compounds, optical materials, nuclear fuels such as UO2 and PuO2, and mixed anionic materials. The document concludes by noting the challenges of obtaining research funding but Jackson's continued work through collaborations and students, and his hopes to continue studying interesting materials problems.

1. 37 years of defect modelling, and
counting. What’s next?
Robert A Jackson
School of Chemical & Physical Sciences
Keele University
Keele, Staffs ST5 5BG, UK
r.a.jackson@keele.ac.uk
@robajackson
http://www.slideshare.net/robajackson

2. Plan of talk
1. Even further back – PhD research
2. First Postdoc – fission gas in UO2
3. A brief Birkbeck experience
4. And so to Keele!
– Zeolites and Shell
– Kodak collaboration
– Molecular Ionic Materials
– Optical Materials
– UO2 revisited
– Current work
5. What next? Some conclusions
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 2

3. Even further back – PhD
research
• My PhD was carried out
under the supervision
of Dr Stuart Walmsley,
on Lattice Dynamics of
Molecular Crystals.
Most of the calculations
were carried out using
UCL’s IBM 360 computer,
using punched cards.
The computer didn’t
store the source code
back then, so that was
also in the card deck …
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 3

4. Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 4
The IBM 360
• Cost $2M in 1966.
• Maximum memory
for running
calculations was
about 100 kb!
• Picture shows card
punch machine and
control terminal.
http://www.uh.edu/engines/epi1703.htm

5. Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 5
PhD research: modelling
molecular solids
• Lattice dynamics
calculations on
molecular solids: CO2,
C2N2 and N2O4
• Diagram shows the CO2
structure (‘dry ice’)

6. First Postdoc - Fission gas in UO2
• My first project with Richard – using his UO2 potential
and electron-gas potentials to represent Xe-O
interactions. This was followed by development of a new
potential, with John Harding and Andy Murray.
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 6

7. Digression - Fission gas in UO2
2018 style
• Some of the calculations published in 1985
were repeated by a project student this year,
using GULP instead of HADES. Similar results
were obtained, although further analysis is
needed.
– The previous calculations were run on a
mainframe computer at Harwell, using a dial-up
link from UCL, while the recent ones were run on
a networked PC using Putty to connect (:
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 7

8. A new UO2 potential
• This new potential was fitted to lattice parameter
measurements, and included calculations of the entropy
of formation of defects using John Harding’s SHEOL
code.
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 8

9. A brief Birkbeck experience
• I then spent nearly two years working as a postdoc
for Dr Paul Barnes at Birkbeck, in the Crystallography
Department (with Tom Blundell as HoD). The project
was an early attempt to model hydration in minerals.
I used the ATMOL code, and some preliminary
results were published …
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 9
Paul in an atypical pose.
(Maybe he took up drinking after I left!)

10. J. Chem. Phys., 93, 3573-3577 (1990)
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 10

11. A move to Keele
In 1986 I joined Richard’s
group at Keele. A 2-year
contract that turned into a
career! I shared an office
with the gentlemen below
(Robin Grimes and
Rajappan Vetrivel).
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018
11
Photos from 1987

12. Modelling zeolites (Shell)
• Earlier work by Richard, Steve Parker, Mick Sanders and
Maurice Leslie had led to potentials initially for SiO2
which were later applied to zeolites.
• My project was funded by Shell, working with Rutger
van Santen and Gijs Ooms:
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 12
During this project I visited and worked
at Shell’s KSLA lab in Amsterdam.

13. This project produced a paper which has been used by
many people starting work on zeolites:
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 13

14. Kodak collaboration
• After the Shell
collaboration finished, I
was part-funded by
Kodak (Rochester, NY)
for 2 years to work on
PZT, PLZT and related
materials.
• During this time I was
working with Roger
Baetzold (right).
• Photo taken at a meeting
held in London (Ontario) in
1989 in honour of Patrick
Jacobs. (With Richard,
Patrick and Yen Tan).
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018
14

15. Molecular ionic materials
• Another change of direction
led to work on molecular
ionic materials, with Kevin
Roberts and David Price.
– Calcium carbonate has been
much studied since, but one
of the earlier papers was the
one shown top right.
• The other paper describes
potential derivation for
perchlorates and an excursion
into morphological modelling
(next slide).
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018
15

16. Calculation of morphologies:
surface and attachment energies.
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 16

17. Optical materials
My interest in optical
materials started through a
collaboration with Mário
Valerio. This involved
modelling dopants in mixed
metal fluorides and
predicting location & optical
behaviour.
As the photo shows,
discussion and refreshment
are important!
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018
17

18. A renaissance of nuclear fuels
modelling
• My return to modelling
nuclear fuels was around
2010, and coincided with
a new collaboration with
Mark Read. Using his
potential fitting
methodology, we derived
new potentials for UO2
and subsequently, PuO2.
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 18

19. Current work - (i) lithium niobate
• Lithium niobate had
earlier been modelled
by Richard, Simon
Tomlinson and Hans
Donnerberg, but the
enduring interest in
the material led to the
derivation of a new
potential. Papers from
then (1991) and 2007
are shown:
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018
19

20. Lithium niobate – current projects
• Location of dopants – some properties (e.g. those
responsible for holographic behaviour) are enhanced
by doping with a range of 2+ and 3+ ions. Their
location is a matter of debate when modelling
results are compared with EXAFS results.
• Modelling of concentration effects – a recent MPhil
student (Ellis Hedges) used supercell calculations to
model ‘realistic’ levels of dopants in LiNbO3. He also
modelled the congruent phase. Writing this work up
is at the top of my list!
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 20

21. Current work - (ii) mixed anionic
materials
• This is very recent work, and has so far only been
‘pump primed’ by two final year research projects.
• These are materials like LaOF, where as well as
doping 3+ ions at the La site, it is possible to change
the O:F ratio so that 2+ or 4+ ions can be doped into
the structure.
– LaOF has some interesting applications as a host material
for phosphors (with rare earth dopants), and there are
potentially other applications with divalent or tetravalent
dopants.
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 21

22. What next? Some conclusions
• Getting research funding externally has become difficult,
and there are issues like the need to be in a CDT to get
EPSRC funding for PhD students etc. Taking on major
admin roles like Acting Head of School doesn’t help
either (but that finished at the end of March!)
• I have been able to keep research going through
collaborations, and with the help of some PhD and MPhil
students.
• There are lots of interesting materials and problems to
study, and I hope to continue doing this.
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018 22

23. Acknowledgements
• Thanks to Richard, Nora
and Zhimei who have very
kindly organised this
meeting.
• Thanks to everyone who
has helped me at various
points in my career.
• And finally, thanks to you
for attending the meeting
and listening!
Modelling Surface and Defect Properties of Materials - UCL, 5-6 April 2018
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24. Unfortunately the Gnome
was too infirm to make the
trip, but sends his best
wishes to all!