Nobuyuki Matubayasi

The proton chemical shift of water is measured at temperatures up to 400°C and densities of 0.19, 0.29, 0.41, 0.49, and 0.60g/cm3. The magnetic susceptibility correction is made in order to express the chemical shift relative to an isolated water molecule in dilute gas. The chemical shift is related to the average number of hydrogen bonds in which a water molecule is involved. It is found that the hydrogen bonding persists at supercritical temperatures and that the average number of hydrogen bon

The energetic representation of the molecular configuration in a dilute solution is introduced to express the solvent distribution around the solute over a one-dimensional coordinate specifying the solute–solvent interaction energy. In this representation, the correspondence is shown to be one-to-one between the set of solute–solvent interaction potentials and the set of solvent distribution functions around the solute. On the basis of the one-to-one correspondence, the Percus–Yevick and hyperne

An approximate functional for the chemical potential of a solute in solution is presented in the energy representation. This functional is constructed by adopting the Percus–Yevick-like approximation in the unfavorable region of the solute–solvent interaction and the hypernetted-chain-like approximation in the favorable region. The chemical potential is then expressed in terms of energy distribution functions in the solution and pure solvent systems of interest, and is given exactly to second or

The method of energy representation for evaluating the solvation free energy is extended to a solute molecule with structural flexibility. When the intramolecular structure of the solute molecule exhibits a strong response to the solute–solvent interaction, the approximate functional for the solvation free energy needs to be modified from the original form presented previously [J. Chem. Phys. 117, 3605 (2002); 118, 2446 (2003)]. In the modification of the functional, the solvation-induced change

The proton chemical shift of water is measured at temperatures up to $400\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ and densities of $0.19$, $0.41$, $0.49$, and $0.60\mathrm{g}/{\mathrm{cm}}^{3}$. The magnetic susceptibility correction is made in order to express the chemical shift relative to an isolated water molecule in dilute gas. Comparison of the chemical shifts of water in neat fluids at high temperatures to those in organic solvents at ambient conditions shows that the hydrogen bondi

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermodynamics of the Hydration Shell. 1. Excess Energy of a Hydrophobic SoluteNobuyuki Matubayasi, Lynne H. Reed, and Ronald M. LevyCite this: J. Phys. Chem. 1994, 98, 41, 10640–10649Publication Date (Print):October 1, 1994Publication History Published online1 May 2002Published inissue 1 October 1994https://pubs.acs.org/doi/10.1021/j100092a040https://doi.org/10.1021/j100092a040research-articleACS PublicationsRequest reuse permissionsArticle Views453Al

The hydration shell model for the excess volume and compressibility is examined. A modified Kirkwood−Buff formula for the excess volume, which is appropriate for use in the canonical ensemble, is presented. Its pressure derivative is shown to be the excess compressibility, which can be expressed as an integral of the local solvent compressibility over the hydration shell. For methane in water, which is chosen as the first application, the local solvent density and compressibility around the solu

A time-reversible molecular dynamics algorithm is presented for rigid bodies in the quarternion representation. The algorithm is developed on the basis of the Trotter factorization scheme, and its structure is similar to that of the velocity Verlet algorithm. When the rigid body is an asymmetric top, its computationally inconvenient Eulerian equation of motion is integrated by combining the computationally convenient solutions to the Eulerian equations of motion for two symmetric tops. It is sho

The rotational dynamics of water in super- and subcritical conditions is investigated by measuring the spin-lattice relaxation time T1 of heavy water (D2O). The experimentally determined T1 is shown to be governed by the quadrupolar relaxation mechanism even in the supercritical conditions and to provide the second-order reorientational correlation time τ2R of the O–D axis of a single water molecule. It is then found that while τ2R decreases rapidly with the temperature on the liquid branch of t

result for methanol at 0.2 g/cm 3 and 400 C reads 1.20.1 (1.30.1). It should be corrected to 1.2 0.1 (1.30.1).

A statistical-mechanical treatment of the molecular binding into lipid membrane is presented in combination with molecular simulation. The membrane solution is viewed as an inhomogeneous, mixed solvent system, and the free energy of solvation of a solute in membrane is computed with a realistic set of potential functions by the method of energy representation. Carbon monoxide, carbon dioxide, benzene, and ethylbenzene are adopted as model solutes to analyze the binding into 1,2-dimyristoyl-sn-gl

The library of isostructural porous frameworks enables a systematic survey to optimize the structure and functionality of porous materials. In contrary to metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), a handful of isostructural frameworks have been reported for hydrogen-bonded organic frameworks (HOFs) due to the weakness of the bonds. Herein, we provide a rule-of-thumb to develop isostructural HOFs, where we demonstrate the construction of the third and fourth generati

ERmod is a software package to efficiently and approximately compute the solvation free energy using the method of energy representation. Molecular simulation is to be conducted at two condensed-phase systems of the solution of interest and the reference solvent with test-particle insertion of the solute. The subprogram ermod in ERmod then provides a set of energy distribution functions from the simulation trajectories, and another subprogram slvfe determines the solvation free energy from the d

A statistical-mechanical treatment of the solubilization in micelle is presented in combination with molecular simulation. The micellar solution is viewed as an inhomogeneous and partially finite, mixed solvent system, and the method of energy representation is employed to evaluate the free-energy change for insertion of a solute into the micelle inside with a realistic set of potential functions. Methane, benzene, and ethylbenzene are adopted as model hydrophobic solutes to analyze the solubili