1
|
Asthagiri DN, Paulaitis ME, Pratt LR. Thermodynamics of Hydration from the Perspective of the Molecular Quasichemical Theory of Solutions. J Phys Chem B 2021; 125:8294-8304. [PMID: 34313434 DOI: 10.1021/acs.jpcb.1c04182] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The quasichemical organization of the potential distribution theorem, molecular quasichemical theory (QCT), enables practical calculations and also provides a conceptual framework for molecular hydration phenomena. QCT can be viewed from multiple perspectives: (a) as a way to regularize an ill-conditioned statistical thermodynamic problem; (b) as an introduction of and emphasis on the neighborship characteristics of a solute of interest; or (c) as a way to include accurate electronic structure descriptions of near-neighbor interactions in defensible statistical thermodynamics by clearly defining neighborship clusters. The theory has been applied to solutes of a wide range of chemical complexity, ranging from ions that interact with water with both long-ranged and chemically intricate short-ranged interactions, to solutes that interact with water solely through traditional van der Waals interations, and including water itself. The solutes range in variety from monatomic ions to chemically heterogeneous macromolecules. A notable feature of QCT is that, in applying the theory to this range of solutes, the theory itself provides guidance on the necessary approximations and simplifications that can facilitate the calculations. In this Perspective, we develop these ideas and document them with examples that reveal the insights that can be extracted using the QCT formulation.
Collapse
Affiliation(s)
- Dilipkumar N Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Michael E Paulaitis
- Center for Nanomedicine, Johns Hopkins School of Medicine, Baltimore, Maryland 21231, United States
| | - Lawrence R Pratt
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| |
Collapse
|
2
|
Muralidharan A, Pratt LR, Chaudhari MI, Rempe SB. Quasi-Chemical Theory with Cluster Sampling from Ab Initio Molecular Dynamics: Fluoride (F -) Anion Hydration. J Phys Chem A 2018; 122:9806-9812. [PMID: 30475612 DOI: 10.1021/acs.jpca.8b08474] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Accurate predictions of the hydration free energy for anions typically has been more challenging than that for cations. Hydrogen bond donation to the anion in hydrated clusters such as F(H2O) n - can lead to delicate structures. Consequently, the energy landscape contains many local minima, even for small clusters, and these minima present a challenge for computational optimization. Utilization of cluster experimental results for the free energies of gas-phase clusters shows that even though anharmonic effects are interesting they need not be of troublesome magnitudes for careful applications of quasi-chemical theory to ion hydration. Energy-optimized cluster structures for anions can leave the central ion highly exposed, and application of implicit solvation models to these structures can incur more serious errors than those for metal cations. Utilizing cluster structures sampled from ab initio molecular dynamics simulations substantially fixes those issues.
Collapse
Affiliation(s)
- A Muralidharan
- Department of Chemical and Biomolecular Engineering , Tulane University , New Orleans , Louisiana 70118 , United States
| | - L R Pratt
- Department of Chemical and Biomolecular Engineering , Tulane University , New Orleans , Louisiana 70118 , United States
| | - M I Chaudhari
- Center for Biological and Engineering Sciences , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - S B Rempe
- Center for Biological and Engineering Sciences , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| |
Collapse
|
3
|
Dixit PD, Bansal A, Chapman WG, Asthagiri D. Mini-grand canonical ensemble: Chemical potential in the solvation shell. J Chem Phys 2018; 147:164901. [PMID: 29096517 DOI: 10.1063/1.4993178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Quantifying the statistics of occupancy of solvent molecules in the vicinity of solutes is central to our understanding of solvation phenomena. Number fluctuations in small solvation shells around solutes cannot be described within the macroscopic grand canonical framework using a single chemical potential that represents the solvent bath. In this communication, we hypothesize that molecular-sized observation volumes such as solvation shells are best described by coupling the solvation shell with a mixture of particle baths each with its own chemical potential. We confirm our hypotheses by studying the enhanced fluctuations in the occupancy statistics of hard sphere solvent particles around a distinguished hard sphere solute particle. Connections with established theories of solvation are also discussed.
Collapse
Affiliation(s)
- Purushottam D Dixit
- Department of Systems Biology, Columbia University, New York City, New York 10032, USA
| | - Artee Bansal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Dilip Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| |
Collapse
|
4
|
Bansal A, Chapman WG, Asthagiri D. Quasichemical theory and the description of associating fluids relative to a reference: Multiple bonding of a single site solute. J Chem Phys 2017; 147:124505. [DOI: 10.1063/1.4997663] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Artee Bansal
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
| | - Walter G. Chapman
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
| | - D. Asthagiri
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
| |
Collapse
|
5
|
Bansal A, Valiya Parambathu A, Asthagiri D, Cox KR, Chapman WG. Thermodynamics of mixtures of patchy and spherical colloids of different sizes: A multi-body association theory with complete reference fluid information. J Chem Phys 2017; 146:164904. [PMID: 28456194 DOI: 10.1063/1.4981913] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We present a theory to predict the structure and thermodynamics of mixtures of colloids of different diameters, building on our earlier work [A. Bansal et al., J. Chem. Phys. 145, 074904 (2016)] that considered mixtures with all particles constrained to have the same size. The patchy, solvent particles have short-range directional interactions, while the solute particles have short-range isotropic interactions. The hard-sphere mixture without any association site forms the reference fluid. An important ingredient within the multi-body association theory is the description of clustering of the reference solvent around the reference solute. Here we account for the physical, multi-body clusters of the reference solvent around the reference solute in terms of occupancy statistics in a defined observation volume. These occupancy probabilities are obtained from enhanced sampling simulations, but we also present statistical mechanical models to estimate these probabilities with limited simulation data. Relative to an approach that describes only up to three-body correlations in the reference, incorporating the complete reference information better predicts the bonding state and thermodynamics of the physical solute for a wide range of system conditions. Importantly, analysis of the residual chemical potential of the infinitely dilute solute from molecular simulation and theory shows that whereas the chemical potential is somewhat insensitive to the description of the structure of the reference fluid, the energetic and entropic contributions are not, with the results from the complete reference approach being in better agreement with particle simulations.
Collapse
Affiliation(s)
- Artee Bansal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - D Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Kenneth R Cox
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| |
Collapse
|
6
|
Bansal A, Asthagiri D, Cox KR, Chapman WG. Structure and thermodynamics of a mixture of patchy and spherical colloids: A multi-body association theory with complete reference fluid information. J Chem Phys 2016; 145:074904. [DOI: 10.1063/1.4960985] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Artee Bansal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - D. Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Kenneth R. Cox
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| |
Collapse
|
7
|
|
8
|
Sepehr F, Paddison SJ. The solvation structure and thermodynamics of aqueous vanadium cations. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.08.089] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
9
|
Sarangi R, Frank P, Benfatto M, Morante S, Minicozzi V, Hedman B, Hodgson KO. The x-ray absorption spectroscopy model of solvation about sulfur in aqueous L-cysteine. J Chem Phys 2013. [PMID: 23206038 DOI: 10.1063/1.4767350] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The environment of sulfur in dissolved aqueous L-cysteine has been examined using K-edge x-ray absorption spectroscopy (XAS), extended continuum multiple scattering (ECMS) theory, and density functional theory (DFT). For the first time, bound-state and continuum transitions representing the entire XAS spectrum of L-cysteine sulfur are accurately reproduced by theory. Sulfur K-edge absorption features at 2473.3 eV and 2474.2 eV represent transitions to LUMOs that are mixtures of S-C and S-H σ∗ orbitals significantly delocalized over the entire L-cysteine molecule. Continuum features at 2479, 2489, and 2530 eV were successfully reproduced using extended continuum theory. The full L-cysteine sulfur K-edge XAS spectrum could not be reproduced without addition of a water-sulfur hydrogen bond. Density functional theory analysis shows that although the Cys(H)S⋯H-OH hydrogen bond is weak (∼2 kcal) the atomic charge on sulfur is significantly affected by this water. MXAN analysis of hydrogen-bonding structures for L-cysteine and water yielded a best fit model featuring a tandem of two water molecules, 2.9 Å and 5.8 Å from sulfur. The model included a S(cys)⋯H-O(w1)H hydrogen-bond of 2.19 Å and of 2.16 Å for H(2)O(w1)⋯H-O(w2)H. One hydrogen-bonding water-sulfur interaction alone was insufficient to fully describe the continuum XAS spectrum. However, density functional theoretical results are convincing that the water-sulfur interaction is weak and should be only transient in water solution. The durable water-sulfur hydrogen bond in aqueous L-cysteine reported here therefore represents a break with theoretical studies indicating its absence. Reconciling the apparent disparity between theory and result remains the continuing challenge.
Collapse
Affiliation(s)
- Ritimukta Sarangi
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
| | | | | | | | | | | | | |
Collapse
|
10
|
Weber V, Merchant S, Asthagiri D. Communication: Regularizing binding energy distributions and thermodynamics of hydration: Theory and application to water modeled with classical and ab initio simulations. J Chem Phys 2011; 135:181101. [DOI: 10.1063/1.3660205] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Valéry Weber
- IBM Research Division, Zurich Research Laboratory, 8803 Ruschlikon, Switzerland
| | - Safir Merchant
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - D. Asthagiri
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| |
Collapse
|
11
|
Svoboda O, Ončák M, Slavíček P. Simulations of light induced processes in water based on ab initio path integrals molecular dynamics. I. Photoabsorption. J Chem Phys 2011; 135:154301. [DOI: 10.1063/1.3649942] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
12
|
Toxvaerd S, Dyre JC. Role of the first coordination shell in determining the equilibrium structure and dynamics of simple liquids. J Chem Phys 2011; 135:134501. [DOI: 10.1063/1.3643123] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
|
13
|
Affiliation(s)
- Purushottam D Dixit
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | | |
Collapse
|