Dresden 2020 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 71: Modelling and Simulation of Soft Matter II (joint session CPP/DY)
CPP 71.6: Talk
Wednesday, March 18, 2020, 16:15–16:30, ZEU 255
The stability field of the chiral CO2 water hydrate from molecular dynamics simulations — •Marcello Sega1, Jakob Michl2, and Christoph Dellago2 — 1Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Forschungszentrum Jülich, Germany — 2Faculty of Physics, University of Vienna, Austria
Recent experimental evidence[1] shows that the water network characterizing the high-pressure CO2 hydrate[2] is, in fact, ice XVII, which possesses open helicoidal channels giving the structure a chiral nature. The question of the stability field boundaries of this hydrate is still open, and we report on recent molecular dynamics simulations[3] in which we found that the CO2-filled ice XVII is more stable than the sI clathrate and than the mixture of ice VI and dry ice at pressure values ranging from 6 to 18 kbar and in a wide temperature range. We propose a phenomenological correction to take into account the limitation of the model potentials, suggesting that the stability should more realistically range from 6.5 to 13.5 kbar. Our simulation results support the current hypothesis that the chiral CO2 hydrate is stable at temperatures above the melting curve of ice VI.
[1]L. Del Rosso, M. Celli, and L. Ulivi, Nat. Comm. 7, 13394 (2016)
[2]H. Hirai, K. Komatsu, M. Honda, T. Kawamura, Y. Yamamoto, and T. Yagi, The J. Chem. Phys. 133, 124511 (2010)
[3]J. Michl, M. Sega, and C. Dellago, J. Chem. Phys. 151, 104502 (2019)