a priori path integral simulation on the dynamical properties and phenomena of low-temperature quantum molecular systems

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In the present series of studies, the static and dynamical properties of solid and liquid hydrogen have been non-empirically investigated by means of path integral centroid molecular dynamics (CMD) simulations.For solid para-hydrogen, we have obtained the phonon excitations with higher energies than those in previous experimental reports. Although the phonon dispersion in the high energy region in solid para-hydrogen has been definitely determined because of contradictory data reported from the experiments, our present study have thrown an insight into this outstanding controversy.The fundamental transport properties (self-diffusion coefficient, thermal conductivity, shear viscosity, and bulk viscosity) have been evaluated by using the CMD simulations. This work is the first attempt to numerically a priori estimate collective transport properties of any quantum liquids. In particular, the agreement of calculated self-diffusion coefficient and the shear viscosity with experimental values is excellent. On the other hand, the classical molecular dynamics simulations have yield the values much deviated from the experimental ones. This indicates that the essential features of the transport properties of liquid para-hydrogen comes from the quantum effect.The present series of studies are remarkable in that they have resolved the dynamical properties which cannot be revealed by any other computational techniques.