Prof. Dylan Jayatilaka UWA Perth, Australia
Prof., Dr, BSc W.Aust., PhD Camb.
- Associate Professor, School of Molecular Sciences
https://orcid.org/0000-0002-3349-5834
Dylan Jayatilaka completed his Bachelor of Science with Honours in Chemical Physics at The University of Western Australia.
He completed and PhD at Cambridge University in the United Kingdom in Theoretical Chemistry under the supervision of Nicholas Handy.
Thereafter he was a National Research Council (USA) Research Fellow at the NASA Ames research center, and he was an Australian Research Council QE-II Research Fellow, and an Australian Research Council Sebnior Fellow.
Dylan Jayatilaka has been a visiting researcher at the Ecole National Superieure in Paris, and the Universite Henri Poincare (Now Universite de Lorraine), the University of Bremen Germany, and the University of Bern in Switzerland.
Dylan Jayatilaka was appointed at UWA in 2001.
Research interests
Dylan is a quantum chemist and crystallographer with interests in all aspects of theoretical and computational chemistry, but especially quantum chemistry and crystallography.
His PhD was concerned with the calculation of higher analytical derivatives of the Hartree-Fock molecular energy and properties, and he programmed the only existing analytical implementation of the fourth derivatives of the Hartree-Fock energy. Such energy and property derivatives may be used to obtain anharmonic corrections to vibrational energy trransition, vibrational intensities, and various other constants - such perturbation calculations are now known as VPT2.
During his postdoctoral work at NASA, he developed the Z-averaged perturbation theory and coupled cluster theory which imposes restricted symmetry on the required equations with closed-shell cost.
After returning to UWA, his interests turned to X-ray and polarised neutron diffraction. With Dr. Daniel Grimwood, his first Ph.D. student, presented the first "experimentally" determined wavefunction constrained to reproduce the X-ray diffraction experiment. Later, with Dr. Birger Dittrich, he developed the Hirshfeld atom refinement (HAR) method and in a series of papers with co-authors, demonstrated that it is able to obtain hydrogen atom positions and ADPs in agreement with neutron diffraction measurements. This has spawned the field of "Quantum Crystallography". With Prof. Piero Macchi, he chaired the inaugural school in Quantum Crystallography at Erice in 2018.
He spent much time working with Professor Mark Spackman, developing the very popular CrystalExplorer program for visualising decorated Hirshfeld Surfaces, crystal voids. Images from this program are widely seen in the IUCr journals. Also with Spackman, he has developed an efficient four-term physically-based method for calculating molecular interaction energies in crystals which is amongst the fastest and most accurate currently available. With Ben Corry he was involved in developing methods to model hydrated ions in ion channel proteins, and methods to model Forster resonance energy transfer (FRET).
Dylan’s scientific output has earned > 17 700 citations. His H index = 50
More info about Dylan on the web page:
https://research-repository.uwa.edu.au/en/persons/dylan-jayatilaka
Lecture 3: Dylan Jayatilaka
Quantum Crystallography: Past, Present, and Future
Prof. Dylan Jayatilaka UWA Perth, Australia
Abstract
What is quantum crystallography? [1] Is it a hyped-up fad? Is it “theory” or “experiment”? What can it do? Is it useful? Why has it become a new (perhaps better: reborn) IUCr commision?
The past: At the 2002 IUCr meeting in Geneva (rescheduled from Jerusalem) I was asked to speak after Jerome Karle, Nobel Laureate and one of those who had coined the term quantum crystallography (QCr) [2]. The room was packed, and soon there was a (second order?) phase change in the audience: either asleep or fidgeting. When Karle finished there was an immediate and astounding rush of people to leave. It was a bit disheartening for me; I had to shout over the commotion. Then there was more chaos, as some even turned back. I like to think it was because of me, but more likely it was defeat. I will review some of this 2002 material and show that QCr was in fact born with quantum mechanics itself [3]. I want to also highlight the work of Tibor Koritsanszky, recently lost to us, who together with Ewald medallist Philip Coppens brought about the “golden age” of our field [4].
The present: In a recent Australian Research Council grant application of mine assessor B lamented: “QCr is slowly creeping into crystallographic refinement to provide a better treatment of light i.e. hydrogen atoms … but how useful will it be in the vast majority of structural refinements?”. Even assessor D found it “hard to get excited about hydrogen atoms (sorry)”. Perhaps D is a physicist: only a non-chemist could be so callously unmoved by the proton, which forms the skin of all molecules, and is the fat positive partner of the beauteous electron! Surely these two are the hands of chemistry itself?! But I am actually rather pleased by that creeping comment: to me, it evokes a kind of disease-like inevitability: it resonates with the lack of direct funding [5]. In any case, I will explain why QCr is hard work, and I will review the impressive current progress by several groups.
The future: I think, except for Arthur C. Clarke, there have been no futorologist of note. Nevertheless, I will attempt to describe my vision for the use of model “experimental” wavefunctions to encode much more than just structral information; how QCr, the synthesis of quantum chemistry and crystallography will produce high quality databases worth mining; and how QCr has much to offer cognate fields like single-molecule and electron “diffraction”.
References:
[1] (a) Jayatilaka, D., N. C. (2012). Modern Charge-Density Analysis, edited by C. Gatti & P. Macchi, pp. 213-257. Springer. (b) Grabowsky, S., Genoni, A., Buergi, H.-B. (2017). Chem. Sci. 8, 4159; (c) Genoni, A.., et. al. (2018). Chem. Eur. J. 24, 10881.
[2] Massa, L., Huang, L., Karle, J. (1995). Int. J. Quantum Chem. 56, 371.
[3] James, R.W., Waller, I., Hartree, D.R. (1928) Proc. Royal Soc. London Ser. A 118, 334 [4] Koritsanszky, T.S., Coppens, P. (2001). Chem. Rev. 101, 1583
[5] Take heart east-coast scientists! Research can continue, even in Western Australia where, to paraphrase W. Pauli and P. Doherty, we are not even of the Pacific bogan variety, https://tinyurl.com/jmv6uyne .