First principles centroid molecular dynamics simulation of high pressure ices

Takashi Ikeda

doi:10.1063/1.5003055

First principles centroid molecular dynamics simulation of high pressure ices

J Chem Phys. 2018 Mar 14;148(10):102332. doi: 10.1063/1.5003055.

Author

Takashi Ikeda¹

Affiliation

¹ Synchrotron Radiation Research Center, Quantum Beam Science Research Directorate (QuBS), National Institutes for Quantum and Radiological Science and Technology (QST), 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.

PMID: 29544301
DOI: 10.1063/1.5003055

Abstract

The nuclear quantum effects (NQEs) on the structural, elastic, electronic, and vibrational properties of high pressure ices (HPIs) VIII, VII, and X at 270 K were investigated via first principles centroid molecular dynamics (CMD). Our simulations clearly show that even at relatively high temperature of 270 K, the NQEs play a definite role in the pressure-induced proton order (ice VIII)-disorder (ice VII) transition occurring at ∼30 GPa in our H₂O ice and the subsequent transition to the symmetric phase ice X suggested to occur at ∼80 GPa. The internal pressure computed at constant NVT conditions shows that the NQEs manifest themselves in the equation of state of HPIs. Our employed approach based on first principles CMD for computing vibrational spectra is proved to be able to reproduce well the overall features of the measured infrared and Raman spectra.