Distinct structural and dynamical difference between supercooled and normal liquids of hydrogen molecules

Abstract

Supercooled hydrogen liquid as well as superfluid have continued to elude experimental observation due to rapid crystallization. We computationally realized and investigated supercooled hydrogen liquid by a recently developed non-empirical real-time molecular dynamics method, which describes non-spherical hydrogen molecules with the nuclear quantum effects. We demonstrated that the hydrogen supercooled liquid is not a simply cooled liquid but rather exhibits intrinsic structural and dynamical characters including a precursor of tunneling and superfluidity which neither normal hydrogen liquid nor solid possesses. All of the insights provide a milestone for planning experiments of metastable hydrogen systems like glassy and superfluid states and for identifying various unknown hydrogen phases.

A Gaussian wave packet phase-space representation of quantum canonical statistics

“…We now calculate H, x, and ∆x for the more challenging case of an asymmetric double well potential, defined in one-dimensional, non mass-weighted space as Panels AI and BI of Figure 4 show x and ∆x, respectively, with the accompanying residuals in panels AII and BII, defined using Eq. (52). Despite the greater anharmonicity, both the Gaussian averages and the temperature transitioned averages are close to the exact quantum values for x and ∆x, with errors of 1% or less.…”

“…We intend to explore the use of thermostatted trajectories for the calculation of correlation functions in future work, which will generalise the existing microcanonical approaches [49][50][51][52][53] to finite temperature. This article is concerned with improving the accuracy of the approximate canonical phase-space density and canonical statistical averages.…”

Single-electron quantum dynamics in high-harmonic generation spectrum from LiH molecule: Analysis of potential energy surfaces for electrons constructed from a model of localized Gaussian wave packets with valence-bond spin-coupling

“…Another related issue would be inclusion of nuclear motion. In the present framework, an approximate treatment with nuclear wave packets would be possible [36][37][38][39]. These are open for future examinations.…”

“…In previous publications [32,33], we demonstrated that a model of floating and breathing localized electron wave * E-mail: ando_k@lab.twcu.ac.jp packets (EWP) with non-orthogonal valence-bond (VB) spincoupling [34][35][36][37][38][39][40] can be used to construct potential energy surfaces for single electron motion (ePES) as functions of the EWP positions. In Ref.…”

Potential energy surfaces for electron dynamics modeled by floating and breathing Gaussian wave packets with valence-bond spin-coupling: An analysis of high-harmonic generation spectrum

“…To obtain an alternative perspective, we have been studying a model of localized electron wave packets (EWPs) with non-orthogonal valence-bond (VB) spin-coupling [31][32][33][34]. It was originally developed for a polarizable and reactive forcefield model in condensed phase simulations to be combined with nuclear wave packets for light atoms [35][36][37][38]. For small molecules such as H 2 , LiH, BeH 2 , CH 2 , H 2 O, and NH 3 in * E-mail: ando k@lab.twcu.ac.jp the ground electronic state, the model gives reasonably accurate potential energy surfaces with the minimal number of EWPs [32].…”