FisMat2017 - Submission - View

Abstract's title: Fast and accurate quantum Monte Carlo for molecular crystals
Submitting author: Andrea Zen
Affiliation: University College London
Affiliation Address: Department of Physics and Astronomy, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
Country: United Kingdom
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Jan Gerit Brandenburg (1,2), Jiri Klimes (3), Dario Alfe (1,4), Angelos Michaelides (1,2) (1) Thomas Young Centre and London Centre for Nanotechnology,17–19 Gordon Street, London, WC1H 0AH, U.K. (2) Department of Physics and Astronomy, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K. (3) J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, CZ-18223 Prague 8, Czech Republic and Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, CZ-12116 Prague 2, Czech Republic (4) Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, U.K.
The problem of assessing the stability of molecular crystals is of great interest in science and technology.
The quantity considered is the lattice energy, that is the energy gained by a molecule in the crystal form with respect to vacuum; it ranges from just a few, to hundreds of kJ/mol, while to distinguish between different polymorphs is often necessary to go beyond the chemical accuracy. 
Theoretical approaches are of great interest to complement experimental investigations, as these are difficult,  indirect and potentially incur large error bars.
Many approaches are available already, but those capable to reach subchemical accuracy are thought to have an enormous computational cost which limits their applicability.
We highlight here, via a representative set of eight diverse molecular crystals, the exceptional achievements of quantum Monte Carlo approaches, which is able of high accuracy while being computationally feasible. 
Thus, a wider future application of quantum Monte Carlo is expected in the screening of lots of systems, of use for crystal structure determination, predicting crystal properties, furthering crystal engineering to design novel pharmaceutical compounds with desired physical and mechanical properties.