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Okita K, Ito N, Morishita-Watanabe N, Umakoshi H, Kasahara K, Matubayasi N. Solvation dynamics on the diffusion timescale elucidated using energy-represented dynamics theory. Phys Chem Chem Phys 2024; 26:12852-12861. [PMID: 38623745 DOI: 10.1039/d4cp00235k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Photoexcitation of a solute alters the solute-solvent interaction, resulting in the nonequilibrium relaxation of the solvation structure, often called a dynamic Stokes shift or solvation dynamics. Thanks to the local nature of the solute-solvent interaction, the characteristics of the local solvent environment dissolving the solute can be captured by the observation of this process. Recently, we derived the energy-represented Smoluchowski-Vlasov (ERSV) equation, a diffusion equation for molecular liquids, which can be used to analyze the solvation dynamics on the diffusion timescale. This equation expresses the time development for the solvent distribution on the solute-solvent pair interaction energy (energy coordinate). Since the energy coordinate can effectively treat the solvent flexibility in addition to the position and orientation, the ERSV equation can be utilized in various solvent systems. Here, we apply the ERSV equation to the solvation dynamics of 6-propionyl-2-dimethylamino naphthalene (Prodan) in water and different alcohol solvents (methanol, ethanol, and 1-propanol) for clarifying the differences of the relaxation processes among these solvents. Prodan is a solvent-sensitive fluorescent probe and is thus widely utilized for investigating heterogeneous environments. On the long timescale, the ERSV equation satisfactorily reproduces the relaxation time correlation functions obtained from the molecular dynamics (MD) simulations for these solvents. We reveal that the relaxation time coefficient on the diffusion timescale linearly correlates with the inverse of the translational diffusion coefficients for the alcohol solvents because of the Prodan-solvent energy distributions among the alcohols. In the case of water, the time coefficient deviates from the linear relationship for the alcohols due to the difference in the extent of importance of the collective motion between the water and alcohol solvents.
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Affiliation(s)
- Kazuya Okita
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Natsuumi Ito
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Nozomi Morishita-Watanabe
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Hiroshi Umakoshi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Kento Kasahara
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
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Okita K, Kasahara K, Matubayasi N. Diffusion theory of molecular liquids in the energy representation and application to solvation dynamics. J Chem Phys 2022; 157:244505. [PMID: 36586971 DOI: 10.1063/5.0125432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The generalized Langevin equation (GLE) formalism is a useful theoretical fundament for analyzing dynamical phenomena rigorously. Despite the systematic formulation of dynamics theories with practical approximations, however, the applicability of GLE-based methods is still limited to simple polyatomic liquids due to the approximate treatment of molecular orientations involved in the static molecular liquid theory. Here, we propose an exact framework of dynamics based on the GLE formalism incorporating the energy representation theory of solution, an alternative static molecular liquid theory. A fundamental idea is the projection of the relative positions and orientations of solvents around a solute onto the solute-solvent interaction, namely the energy coordinate, enabling us to describe the dynamics on a one-dimensional coordinate. Introducing systematic approximations, such as the overdamped limit, leads to the molecular diffusion equation in the energy representation that is described in terms of the distribution function of solvents on the energy coordinate and the diffusion coefficients. The present theory is applied to the solvation dynamics triggered by the photoexcitation of benzonitrile. The long-time behavior of the solvation time correlation function is in good agreement with that obtained by the molecular dynamics simulation.
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Affiliation(s)
- Kazuya Okita
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kento Kasahara
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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Yamaguchi T, Yoshida N. Solvation dynamics in electronically polarizable solvents: Theoretical treatment using solvent-polarizable three-dimensional reference interaction-site model theory combined with time-dependent density functional theory. J Chem Phys 2021; 154:044504. [PMID: 33514097 DOI: 10.1063/5.0036289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The theory of solvation structure in an electronically polarizable solvent recently proposed by us, referred to as the "solvent-polarizable three-dimensional reference interaction-site model theory," is extended to dynamics in this study through the combination with time-dependent density functional theory. Test calculations are performed on model charge-transfer systems in water, and the effects of electronic polarizability on solvation dynamics are examined. The electronic polarizability slightly retards the solvation dynamics. This is ascribed to the decrease in the curvature of the nonequilibrium free energy profile along the solvation coordinate. The solvent relaxation is bimodal, and the faster and the slower modes are assigned to the reorientational and the translational modes, respectively, as was already reported by the surrogate theory combined with the site-site Smoluchowski-Vlasov equation. The relaxation path along the solvation coordinate is a little higher than the minimum free energy path because the translational mode is fixed in the time scale of the reorientational relaxation.
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Affiliation(s)
- Tsuyoshi Yamaguchi
- Graduate School of Engineering, Nagoya University, Chikusa, Nagoya 464-8603, Japan
| | - Norio Yoshida
- Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819-0395, Japan
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Kasahara K, Sato H. Dynamics theory for molecular liquids based on an interaction site model. Phys Chem Chem Phys 2017; 19:27917-27929. [DOI: 10.1039/c7cp05423h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Dynamics theories for molecular liquids based on an interaction site model have been developed over the past few decades and proved to be powerful tools to investigate various dynamical phenomena.
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Affiliation(s)
- Kento Kasahara
- Department of Molecular Engineering
- Kyoto University
- Japan
| | - Hirofumi Sato
- Department of Molecular Engineering and Elements Strategy for Catalysts and Batteries (ESICB)
- Kyoto University
- Japan
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Kasahara K, Sato H. A theory of diffusion controlled reactions in polyatomic molecule system. J Chem Phys 2016; 145:194502. [DOI: 10.1063/1.4967400] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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6
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Yamaguchi T. Mode-coupling theoretical study on the roles of heterogeneous structure in rheology of ionic liquids. J Chem Phys 2016; 144:124514. [PMID: 27036468 DOI: 10.1063/1.4944679] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Theoretical calculations of the rheological properties of coarse-grained model ionic liquids were performed using mode-coupling theory. The nonpolar part of the cation was systematically increased in order to clarify the effects of the heterogeneous structure on shear viscosity. The shear viscosity showed a minimum as the function of the size of the nonpolar part, as had been reported in literatures. The minimum was ascribed to the interplay between the increase in the shear relaxation time and the decrease in the high-frequency shear modulus with increasing the size of the nonpolar part of the cation. The ionic liquids with symmetric charge distribution of cations were less viscous than those with asymmetric cations, which is also in harmony with experiments. The theoretical analysis demonstrated that there are two mechanisms for the higher viscosity of the asymmetric model. The first one is the direct coupling between the domain dynamics and the shear stress. The second one is that the microscopic dynamics within the polar domain is retarded due to the nonlinear coupling with the heterogeneous structure.
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Affiliation(s)
- Tsuyoshi Yamaguchi
- Department of Molecular Design and Engineering, Graduate School of Engineering, Furo-cho B2-3 (611), Chikusa, Nagoya, Aichi 464-8603, Japan
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Lin SR, Tang PH, Wu TM. Local structural effects on orientational relaxation of OH-bond in liquid water over short to intermediate timescales. J Chem Phys 2014; 141:214505. [PMID: 25481150 DOI: 10.1063/1.4902372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
By simulating the rigid simple point charge extended model at temperature T = 300 K, the orientational relaxation of the OH-bond in water was investigated over short to intermediate timescales, within which molecules undergo inertial rotation and libration and then enter the rotational diffusion regime. According to the second-cumulant approximation, the orientational time correlation function (TCF) of each axis that is parallel or perpendicular to an OH-bond is related to an effective rotational density of states (DOS), which is determined using the power spectra of angular velocity autocorrelation functions (AVAFs) of the other two axes. In addition, the AVAF power spectrum of an axis was approximated as the rotational stable instantaneous normal mode (INM) spectrum of the axis. As described in a previous study [S. L. Chang, T. M. Wu, and C. Y. Mou, J. Chem. Phys. 121, 3605 (2004)], simulated molecules were classified into subensembles, according to either the local structures or the H-bond configurations of the molecules. For global molecules and the classified subensembles, the simulation results for the first- and second-rank orientational TCFs were compared with the second-cumulant predictions obtained using the effective rotational DOSs and the rotational stable-INM spectra. On short timescales, the OH-bond in water behaves similar to an inertial rotor and its anisotropy is lower than that of a water molecule. For molecules with three or more H-bonds, the OH-bond orientational TCFs are characterized by a recurrence, which is an indication for libration of the OH-bond. The recurrence can generally be described by the second-cumulant prediction obtained using the rotational stable-INM spectra; however, the orientational TCFs after the recurrence switch to a behavior similar to that predicted using the AVAF power spectra. By contrast, the OH-bond orientational TCFs of molecules initially connected with one or two H-bonds decay monotonically or exhibit a weak recurrence, indicating rapid relaxation into the rotational diffusion regime after the initial Gaussian decay. In addition to accurately describing the Gaussian decay, the second-cumulant predictions formulated using the rotational stable-INM spectra and the AVAF power spectra serve as the upper and lower limits, respectively, for the OH-bond orientational TCFs of these molecules after the Gaussian decay.
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Affiliation(s)
- S R Lin
- Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan
| | - Ping-Han Tang
- Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan
| | - Ten-Ming Wu
- Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan
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Yamaguchi T, Koda S. Roles of translational and reorientational modes in translational diffusion of high-pressure water: Comparison with soft-core fluids. J Chem Phys 2011; 134:234506. [DOI: 10.1063/1.3601054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Yamaguchi T, Koda S. Mode-coupling theoretical analysis of transport and relaxation properties of liquid dimethylimidazolium chloride. J Chem Phys 2010; 132:114502. [PMID: 20331300 DOI: 10.1063/1.3354117] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The mode-coupling theory for molecular liquids based on the interaction-site model is applied to a representative molecular ionic liquid, dimethylimidazolium chloride, and dynamic properties such as shear viscosity, self-diffusion coefficients, reorientational relaxation time, electric conductivity, and dielectric relaxation spectrum are analyzed. Molecular dynamics (MD) simulation is also performed on the same system for comparison. The theory captures the characteristics of the dynamics of the ionic liquid qualitatively, although theoretical relaxation times are several times larger than those from the MD simulation. Large relaxations are found in the 100 MHz region in the dispersion of the shear viscosity and the dielectric relaxation, in harmony with various experiments. The relaxations of the self-diffusion coefficients are also found in the same frequency region. The dielectric relaxation spectrum is divided into the contributions of the translational and reorientational modes, and it is demonstrated that the relaxation in the 100 MHz region mainly stems from the translational modes. The zero-frequency electric conductivity is close to the value predicted by the Nernst-Einstein equation in both MD simulation and theoretical calculation. However, the frequency dependence of the electric conductivity is different from those of self-diffusion coefficients in that the former is smaller than the latter in the gigahertz-terahertz region, which is compensated by the smaller dispersion of the former in the 100 MHz region. The analysis of the theoretical calculation shows that the difference in their frequency dependence is due to the different contribution of the short- and long-range liquid structures.
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Affiliation(s)
- T Yamaguchi
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho B2-3(611), Chikusa, Nagoya, Aichi 464-8603, Japan.
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Ishizuka R, Hirata F. Dynamics of the solvent around a solute: generalized Langevin theory. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:011202. [PMID: 20365359 DOI: 10.1103/physreve.81.011202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Indexed: 05/29/2023]
Abstract
The generalized Langevin theory for a solution has been derived as the infinite dilution limit of the theory for a two component mixture. Following a similar formalism, the mode coupling approximations of the memory kernel have been also obtained. We have applied this method for one component bulk liquid of Lennard-Jones spheres and proved this approximation theoretically. The analysis of the space and time pair correlation proposed by Van Hove has been carried out as a function of solute particle sizes. It is found that the size of the solute particle is deeply related to the relaxation process of the solvation structure characterized around a solute particle at equilibrium. We have also investigated the relation between the different thermodynamic environments and relaxation process. From these studies, we have obtained the useful information about the rapidity of the relaxation of the solvation structure around a solute at equilibrium.
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Affiliation(s)
- R Ishizuka
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California 92039-0365, USA
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11
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Okamura M, Mori H. Time correlation functions in a similarity approximation for one-dimensional turbulence. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:056312. [PMID: 19518567 DOI: 10.1103/physreve.79.056312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 04/17/2009] [Indexed: 05/27/2023]
Abstract
The projection operator formalism yields a time evolution equation for the time correlation function Un(t) of the chaotic modes of interest in terms of the memory function Gamman(t). On the assumption of similarity between Un(t) and Gamman(t), this equation leads to a closed equation for Un(t), which yields the asymptotic behavior of the time correlation function Un(t) and the corresponding power spectrum In(omega) analytically. Thus it turns out that the time correlation function takes the algebraic form 1/(1+t2) for t-->0 as predicted previously, and can be classified into three decay forms for t-->infinity according to the wave number kn: the exponential decay e(-t), the oscillatory exponential decay e(-t) cos t, and the oscillatory power-law decay t(-3/2) cos t. All the corresponding power spectra form a dual structure which is Lorentzian as omega-->0 and decays exponentially as omega-->infinity. In the entire domain 0<or=t<infinity, solutions to the closed equation are quite consistent with the numerical results for small kn, while they are consistent with those for large kn, except for the phase. In the case that the integral time scale of Un(t) is equal to that of Gamman(t), the closed equation is identical to the direct interaction approximation equation for fluid turbulence in the limit kn-->infinity.
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Affiliation(s)
- Makoto Okamura
- Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan
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Yamaguchi T, Furuhashi H, Matsuoka T, Koda S. Dynamic Solvophobic Effect and Its Cooperativity in the Hydrogen-bonding Liquids Studied by Dielectric and Nuclear Magnetic Resonance Relaxation. J Phys Chem B 2008; 112:16633-41. [DOI: 10.1021/jp807473c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tsuyoshi Yamaguchi
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho B2-3(611), Chikusa, Nagoya, Aichi 464-8603, Japan
| | - Hiroki Furuhashi
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho B2-3(611), Chikusa, Nagoya, Aichi 464-8603, Japan
| | - Tatsuro Matsuoka
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho B2-3(611), Chikusa, Nagoya, Aichi 464-8603, Japan
| | - Shinobu Koda
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho B2-3(611), Chikusa, Nagoya, Aichi 464-8603, Japan
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Kobryn AE, Yamaguchi T, Hirata F. Site-site memory equation approach in study of density/pressure dependence of translational diffusion coefficient and rotational relaxation time of polar molecular solutions: acetonitrile in water, methanol in water, and methanol in acetonitrile. J Chem Phys 2007; 122:184511. [PMID: 15918733 DOI: 10.1063/1.1884998] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present results of the theoretical study and numerical calculation of the dynamics of molecular liquids based on the combination of the memory equation formalism and the reference interaction site model (RISM). Memory equations for the site-site intermediate scattering functions are studied in the mode-coupling approximation for the first-order memory kernels, while equilibrium properties such as site-site static structure factors are deduced from RISM. The results include the temperature-density (pressure) dependence of translational diffusion coefficients D and orientational relaxation times tau for acetonitrile in water, methanol in water, and methanol in acetonitrile--all in the limit of infinite dilution. Calculations are performed over the range of temperatures and densities employing the extended simple point charge model for water and optimized site-site potentials for acetonitrile and methanol. The theory is able to reproduce qualitatively all main features of temperature and density dependences of D and tau observed in real and computer experiments. In particular, anomalous behavior, i.e, the increase in mobility with density, is observed for D and tau of methanol in water, while acetonitrile in water and methanol in acetonitrile do not show deviations from the ordinary behavior. The variety exhibited by the different solute-solvent systems in the density dependence of the mobility is interpreted in terms of the two competing origins of friction, which interplay with each other as density increases: the collisional and dielectric frictions which, respectively, increase and decrease with increasing density.
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Affiliation(s)
- Alexander E Kobryn
- Department of Theoretical Study, Institute for Molecular Science, Myodaiji, Okazaki, Aichi 444-8585, Japan
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Yamaguchi T, Matsuoka T, Koda S. Mode-coupling study on the dynamics of hydrophobic hydration. J Chem Phys 2006; 120:7590-601. [PMID: 15267671 DOI: 10.1063/1.1687319] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The molecular motion of water in water-hydrophobic solute mixtures was investigated by the mode-coupling theory for molecular liquids based on the interaction-site description. When the model Lennard-Jones solute was mixed with water, both the translational and reorientational motions of solvent water become slower, in harmony with various experiments and molecular dynamics simulations. We compared the mechanism of the slowing down with that of the pressure dependence of the molecular motion of neat water [T. Yamaguchi, S.-H. Chong, and F. Hirata, J. Chem. Phys. 119, 1021 (2003)]. We found that the decrease in the solvent mobility caused by the solute can essentially be elucidated by the same mechanism: That is, the fluctuation of the number density of solvent due to the cavity formation by the solute strengthens the friction on the collective polarization through the dielectric friction mechanism: We also employed the solute molecule that is the same as solvent water except for the amount of partial charges, in order to alter the strength of the solute-solvent interaction continuously. The mobility of the solvent water was reduced both by the hydrophobic and strongly hydrophilic solutes, but it was enhanced in the intermediate case. Such a behavior was discussed in connection with the concept of positive and negative hydrations.
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Affiliation(s)
- T Yamaguchi
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, Aichi 464-8603, Japan.
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Kobryn A, Yamaguchi T, Hirata F. Study of anomalous mobility of polar molecular solutions by means of the site–site memory equation formalism. J Mol Liq 2006. [DOI: 10.1016/j.molliq.2005.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Yamaguchi T, Matsuoka T, Koda S. Mode-coupling study on the dynamics of hydrophobic hydration II: Aqueous solutions of benzene and rare gases. Phys Chem Chem Phys 2006; 8:737-45. [PMID: 16482314 DOI: 10.1039/b514196f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The dynamic properties of both the solute and solvent of the aqueous solution of benzene, xenon and neon are calculated by the mode-coupling theory for molecular liquids based on the interaction-site model. The B-coefficients of the reorientational relaxation and the translational diffusion of the solvent are evaluated from their dependence on the concentration of the solute, and the reorientational relaxation time of water within the hydration shell is estimated based on the two-state model. The reorientational relaxation times of water in the bulk and within the hydration shell, that of solute, and the translational diffusion coefficients of solute and solvent, are calculated at 0-30 degrees C. The temperature dependence of these dynamic properties is in qualitative agreement with that of NMR experiment reported by Nakahara et al. (M. Nakahara, C. Wakai, Y. Yoshimoto and N. Matubayasi, J. Phys. Chem., 1996, 100, 1345-1349, ref. 36), although the agreement of the absolute values is not so good. The B-coefficients of the reorientational relaxation times for benzene, xenon and neon solution are correlated with the hydration number and the partial molar volume of the solute. The proportionality with the latter is better than that with the former. These results support the mechanism that the retardation of the mobility of water is caused by the cavity formation of the solute, as previously suggested by us (T. Yamaguchi, T. Matsuoka and S. Koda, J. Chem. Phys., 2004, 120, 7590-7601, ref. 34), rather than the conventional one that the rigid hydration structure formed around the hydrophobic solute reduces the mobility of water.
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Affiliation(s)
- T Yamaguchi
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, Aichi 464-8603, Japan.
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Abstract
We present a microscopic theory of equilibrium solvation in solvents with zero dipole moment and nonzero quadrupole moment (quadrupolar solvents). The theory is formulated in terms of autocorrelation functions of the quadrupolar polarization (structure factors). It can be therefore applied to an arbitrary dense quadrupolar solvent for which the structure factors are defined. We formulate a simple analytical perturbation treatment for the structure factors. The solute is described by coordinates, radii, and partial charges of constituent atoms. The theory is tested on Monte Carlo simulations of solvation in model quadrupolar solvents. It is also applied to the calculation of the activation barrier of electron transfer reactions in a cleft-shaped donor-bridge-acceptor complex dissolved in benzene with the structure factors of quadrupolar polarization obtained from molecular-dynamics simulations.
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Affiliation(s)
- Anatoli A Milischuk
- Department of Chemistry and Biochemistry, Arizona State University, P.O. Box 871604, Tempe, Arizona 85287-1604, USA
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Nishiyama K, Yamaguchi T, Hirata F, Okada T. Solvation dynamics in water investigated by RISM/mode-coupling theory. J Mol Liq 2005. [DOI: 10.1016/j.molliq.2004.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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19
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Pressure dependence of diffusion coefficient and orientational relaxation time for acetonitrile and methanol in water: RISM/mode-coupling study. J Mol Liq 2005. [DOI: 10.1016/j.molliq.2004.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Yamaguchi T, Chong SH, Hirata F. Mode-coupling analysis of the translational and rotational diffusion of polar liquids; acetonitrile and water. J Mol Liq 2004. [DOI: 10.1016/j.molliq.2003.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Yamaguchi T, Chong SH, Hirata F. Theoretical study of the molecular motion of liquid water under high pressure. J Chem Phys 2003. [DOI: 10.1063/1.1578624] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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YAMAGUCHI T, CHONG SH, HIRATA F. Dielectric relaxation spectrum of water studied by the site—site generalized Langevin/modified mode-coupling theory. Mol Phys 2003. [DOI: 10.1080/00268970031000092977] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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