Hydrophobic hydration of inert gases: Thermodynamic properties, inherent structures, and normal-mode analysis

Hideki Tanaka, Koichiro Nakanishi

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Computer simulations on water and aqueous solutions of noble gases have been carried out in order to study the structures of water around a solute. The hydration energy and free energy evaluated for neon (Ne) and xenon (Xe) solutions in the present study were in good agreement with those by experiments. The detailed hydration structures were investigated by means of the so called inherent structures and normal-mode analyses. It was found that the positive excess free energy in the hydration of Xe arises from a decrease in the number of distinct potential-energy minima in configuration space and that the free energy increase in the Ne solution is due partly to the decrease in the number of the potential minima and partly to the anharmonic modes which are harder than those in pure water. The soft anharmonic modes in the Xe solution were almost equivalent to those in pure water. The introduction of a Xe solute gives rise to a change in water structure to a clathrate-like structure and yields an increase in population of the cyclic pentamer connected by hydrogen bonds, which leads to the exothermic hydration.

Original languageEnglish
Pages (from-to)3719-3727
Number of pages9
JournalThe Journal of Chemical Physics
Volume95
Issue number5
Publication statusPublished - 1991
Externally publishedYes

Fingerprint

Noble Gases
Xenon
Hydration
hydration
rare gases
Thermodynamic properties
thermodynamic properties
xenon
Water
Neon
Free energy
water
free energy
neon
solutes
clathrates
Potential energy
Hydrogen bonds
computerized simulation
potential energy

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Hydrophobic hydration of inert gases : Thermodynamic properties, inherent structures, and normal-mode analysis. / Tanaka, Hideki; Nakanishi, Koichiro.

In: The Journal of Chemical Physics, Vol. 95, No. 5, 1991, p. 3719-3727.

Research output: Contribution to journalArticle

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