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International Year of Light - Charlie McMonagle

Charlie McMonagle

Tell us about your PhD project

Crystallography is one of the foremost tools to characterise crystalline materials. 2014 was the international year of crystallography and 2015 is also an important year as we use X-ray light to scatter through our sample. From the pattern of diffracted rays the chemical composition of almost all crystals can be determined. These can range from simple salts to molecular magnets, right up to proteins.

Here at Edinburgh we specialise in high pressure crystallography particularly looking at metal organic framework materials. These systems are of particular interest for gas storage and hydrocarbon separation.

We are able to look at our samples under extreme pressures by using diamond anvil cells in which we can easily go to pressures in excess of 50,000 atmospheres (atm), or in other words more than 50 times the pressure at the bottom of the deepest oceans on earth.

However, as impressive as these pressures are, as we look at softer and more complex materials many of their most interesting behaviours are seen far below these pressures. Diamond anvil cells were designed to reach incredibly high pressures but at a cost. Due to forming a seal with a tungsten gasket between the two diamonds looking at pressures below 2,000 atm is very difficult and increasing the pressure by less than 1,000 atm at a time is almost impossible. In some cases the systems we are looking at have been completely destroyed by the pressure required just to seal the cell shut.

This is where my project comes in. I aim to develop a new pressure cell to allow the investigation of materials in this currently inaccessible moderate pressure regime (0 ??? 4,000 atm) with unprecedented accuracy. As material chemists we are interested in looking in detail at structural changes, phase transitions, the calculation of bulk moduli and many other fundamental properties of new materials. These pressures are still extremely high but they are industrially accessible opening up many possibilities for real world applications.

Personally I would love to investigate how extremophiles can survive at the bottom of our deepest oceans under incredible pressures on a molecular level. 

Why is light important to your research?

Light is completely fundamental to this technique as it is based around using X-ray light to interact with the sample. This project is in collaboration with Diamond Light Source, the UK's national synchrotron science facility based in Oxfordshire. Their facilities make it possible for this project to get off the ground, not just because of the scale of the instruments but also the high flux and brilliance of the beam. This allows data to be collected from sample environments that that would be impossible on a lab source and it makes it extremely quick to do so.

Diamond Light Source synchrotron

Image from Diamond Light Source

Describe your average day of PhD work here in the School of Chemistry

At the moment my main project has me at my desk reading, learning and designing. Being a chemist by trade the engineering aspects of this project provide a steep learning curve!

Alongside the cell development I am working on several crystallographic projects and this is my chance to get in the lab and do some ???real??? science. Selecting and manipulating crystals so small you can???t even see them with the naked eye takes some practice but its highly rewarding to pick a gem out of the rough.

Being half funded by Diamond Light I will be spending more time down there over the next couple of years. This will be a great opportunity to live and work at a central facility and be exposed to some of the most exciting science in the UK.

What do you enjoy doing when you are not in the lab?

In Edinburgh I have played for the University Shinty team for 6 years and this is a large part of my time outside work. With the various training sessions and matches along with a good social calendar it has been a large part of life here in Edinburgh.

Through the summer I am looking forward to getting back out on the water with the start of the sailing season along with taking some evening bike rides to work off the far too many Easter eggs. But if you really want to know come find me at the folk session in the Ensign Ewart!

What is your favourite chemical reaction?

Maybe I am cheating a little bit here but with spring well on its way and the first buds on the trees my favourite chemical reaction would have to be photosynthesis. This is the conversion of CO2 and water to sugars through the use of light with a most valuable waste product of O2.

To me this is one of the most fundamental reactions to life and yet so easy to overlook, so it???s lovely every spring to see the nature kick back in to life as a reminder to us all.