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SUMMARY:Nuclear Quantum Effects – Fast and Accurate - Venkat Kapil\, EPF
 L
DTSTART:20200219T141500Z
DTEND:20200219T151500Z
UID:TALK138652@talks.cam.ac.uk
CONTACT:Lisa Masters
DESCRIPTION:Quantum nuclear effects plays a central role in determining pr
 operties of systems that contain light nuclei. For instance\, the large de
 viation of the heat capacity of a solid from the Delong’s Petit limit an
 d of the particle momentum distribution from the Maxwell-Boltzmann behavio
 ur are direct manifestations of the quantum nature of nuclei. While these 
 effects can be accurately modelled in atomistic simulations by employing t
 he imaginary time path integral (PI) technique [1]\, the high computationa
 l cost of running PI simulations has prevented their widespread use. In th
 is talk\, I will introduce molecular dynamics based methods [2\, 3\, 4\, 5
 ] that substantially reduce the computational cost of PI simulations and t
 heir implementation in an open source software i-PI. [6] Going beyond benc
 hmarks\, I will demonstrate the relevance of these advances by studying di
 fferent properties and classes of materials – such as the proton momentu
 m distribution in water that relates to the local structure of protons in 
 ice [4] and facilitates interpretation of complex Deep Inelastic Neutron s
 cattering experiments\, quantum effects that facilitate isotope separation
  in porous organic cages [7]\, tuning of thermal properties of metal-organ
 ic cages loaded with greenhouse gases [5]\, and quantitative estimation of
  quantum mechanical effects that stabilize pharmaceutically active molecul
 ar crystals [8] – at a fraction of the computational cost if using conve
 ntional techniques.\nReferences\n[1] David Chandler and Peter G. Wolynes. 
 Exploiting the isomorphism between quantum theory and classical statistica
 l mechanics of polyatomic fluids. The Journal of Chemical Physics\, 74(7):
 4078– 4095\, April 1981.\n[2] V. Kapil\, J. VandeVondele\, and M. Ceriot
 ti. Accurate molecular dynamics and nuclear quantum effects at low cost by
  multiple steps in real and imaginary time: Using density functional theor
 y to accelerate wavefunction methods. The Journal of Chemical Physics\, 14
 4(5):054111\, February 2016.\n[3] Venkat Kapil\, J ̈org Behler\, and Mich
 ele Ceriotti. High order path integrals made easy. The Journal of Chemical
  Physics\, 145(23):234103\, December 2016.\n[4] Venkat Kapil\, Alice Cuzzo
 crea\, and Michele Ceriotti. Anisotropy of the Proton Momentum Distributio
 n in Water. The Journal of Physical Chemistry B\, 122(22):6048–6054\, Ju
 ne 2018.\n[5] Venkat Kapil\, Jelle Wieme\, Steven Vandenbrande\, Aran Lama
 ire\, Veronique Van Speybroeck\, and Michele Ceriotti. Modeling the Struct
 ural and Thermal Properties of Loaded Metal–Organic Frameworks. An Inter
 play of Quantum and Anharmonic Fluctuations. Journal of Chemical Theory an
 d Computation\, 15(5):3237–3249\, May 2019.\n[6] Venkat Kapil\, Mariana 
 Rossi\, Ondrej Marsalek\, Riccardo Petraglia\, Yair Litman\, Thomas Spura\
 , Bingqing Cheng\, Alice Cuzzocrea\, Robert H. Meißner\, David M. Wilkins
 \, Benjamin A. Hel- frecht\, Przemysl􏰀aw Juda\, S ́ebastien P. Bienven
 ue\, Wei Fang\, Jan Kessler\, Igor Poltavsky\, Steven Vandenbrande\, Jelle
  Wieme\, Clemence Corminboeuf\, Thomas D. Ku ̈hne\, David E. Manolopou- l
 os\, Thomas E. Markland\, Jeremy O. Richardson\, Alexandre Tkatchenko\, Ga
 reth A. Tribello\, Veronique Van Speybroeck\, and Michele Ceriotti. i-PI 2
 .0: A universal force engine for advanced molecular simulations. Computer 
 Physics Communications\, 236:214–223\, March 2019.\n[7] Ming Liu\, Linda
  Zhang\, Marc A. Little\, Venkat Kapil\, Michele Ceriotti\, Siyuan Yang\, 
 Lifeng Ding\, Daniel L. Holden\, Rafael Balderas-Xicoht ́encatl\, Donglin
  He\, Rob Clowes\, Samantha Y. Chong\, Gisela Schu ̈tz\, Linjiang Chen\, 
 Michael Hirscher\, and Andrew I. Cooper. Barely porous organic cages for h
 ydrogen isotope separation. Science\, 366(6465):613–620\, November 2019.
 \n[8] Venkat Kapil\, Edgar Engel\, Mariana Rossi\, and Michele Ceriotti. A
 ssessment of Approxi- mate Methods for Anharmonic Free Energies. Journal o
 f Chemical Theory and Computation\, 15(11):5845–5857\, November 2019.
LOCATION:Department of Chemistry\, Cambridge\, Unilever lecture theatre
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