Molecular dynamics simulation of the order-disorder phase transition in solidNaNO2

Abstract

We present molecular dynamics simulations of solid NaNO 2 using pair potentials with the rigid-ion model. The crystal potential surface is calculated by using an a priori method which integrates the ab initio calculations with the Gordon-Kim electron gas theory. This approach is carefully examined by using different population analysis methods and comparing the intermolecular interactions resulting from this approach with those from the ab initio Hartree-Fock calculations. Our numerics show that the ferroelectric-paraelectric phase transition in solid NaNO 2 is triggered by rotation of the nitrite ions around the crystallographical c axis, in agreement with recent x-ray experiments ͓Gohda et al., Phys. Rev. B 63, 14101 ͑2000͔͒. The crystal-field effects on the nitrite ion are also addressed. An internal charge-transfer effect is found.

Ab initio molecular dynamics simulations of the ferroelectric-paraelectric phase transition in sodium nitrite

“…Early molecular dynamics (MD) simulations with Born-Mayer pair potentials were not able to reproduce the ferro-electric low-temperature phase [21][22][23][24]. At first in 2003, Yin et al were able to perform MD simulations, which successfully predicted the low-temperature ferroelectric phase [25].…”

Probing nitrite ion dynamics in NaNO2 crystals by solid‐state 17O NMR

“…These NaNO 2 structures have been extensively examined in the past by X‐ray diffraction, neutron diffraction, 14 N NQR, and solid‐state NMR ( 23 Na and 15 N) . There are also molecular dynamics (MD) simulations on the rotational barriers for motions in solid NaNO 2 . These previous studies have produced overwhelming evidence suggesting that the rotation of about the crystallographic c ‐axis as the mechanism of the polarization reversal in the high‐temperature paraelectric phase.…”