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Jaugstetter M, Blanc N, Kratz M, Tschulik K. Electrochemistry under confinement. Chem Soc Rev 2022; 51:2491-2543. [PMID: 35274639 DOI: 10.1039/d1cs00789k] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Although the term 'confinement' regularly appears in electrochemical literature, elevated by continuous progression in the research of nanomaterials and nanostructures, up until today the various aspects of confinement considered in electrochemistry are rather scattered individual contributions outside the established disciplines in this field. Thanks to a number of highly original publications and the growing appreciation of confinement as an overarching link between different exciting new research strategies, 'electrochemistry under confinement' is the process of forming a research discipline of its own. To aid the development a coherent terminology and joint basic concepts, as crucial factors for this transformation, this review provides an overview on the different effects on electrochemical processes known to date that can be caused by confinement. It also suggests where boundaries to other effects, such as nano-effects could be drawn. To conceptualize the vast amount of research activities revolving around the main concepts of confinement, we define six types of confinement and select two of them to discuss the state of the art and anticipated future developments in more detail. The first type concerns nanochannel environments and their applications for electrodeposition and for electrochemical sensing. The second type covers the rather newly emerging field of colloidal single entity confinement in electrochemistry. In these contexts, we will for instance address the influence of confinement on the mass transport and electric field distributions and will link the associated changes in local species concentration or in the local driving force to altered reaction kinetics and product selectivity. Highlighting pioneering works and exciting recent developments, this educational review does not only aim at surveying and categorizing the state-of-the-art, but seeks to specifically point out future perspectives in the field of confinement-controlled electrochemistry.
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Affiliation(s)
- Maximilian Jaugstetter
- Analytical Chemistry II, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany.
| | - Niclas Blanc
- Analytical Chemistry II, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany.
| | - Markus Kratz
- Analytical Chemistry II, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany.
| | - Kristina Tschulik
- Analytical Chemistry II, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany.
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Harvey JA, Thompson WH. Solute location in a nanoconfined liquid depends on charge distribution. J Chem Phys 2015; 143:044701. [DOI: 10.1063/1.4926936] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jacob A. Harvey
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
| | - Ward H. Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
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Martinez F, Hanna G. Assessment of approximate solutions of the quantum–classical Liouville equation for dynamics simulations of quantum subsystems embedded in classical environments. MOLECULAR SIMULATION 2014. [DOI: 10.1080/08927022.2014.923573] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Patra S, Pandey AK, Sen D, Ramagiri SV, Bellare JR, Mazumder S, Goswami A. Redox decomposition of silver citrate complex in nanoscale confinement: an unusual mechanism of formation and growth of silver nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2460-2469. [PMID: 24533743 DOI: 10.1021/la4048787] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We demonstrate for the first time the intrinsic role of nanoconfinement in facilitating the chemical reduction of metal ion precursors with a suitable reductant for the synthesis of metal nanoparticles, when the identical reaction does not occur in bulk solution. Taking the case of citrate reduction of silver ions under the unusual condition of [citrate]/[Ag(+)] ≫ 1, it has been observed that the silver citrate complex, stable in bulk solution, decomposes readily in confined nanodomains of charged and neutral matrices (ion-exchange film and porous polystyrene beads), leading to the formation of silver nanoparticles. The evolution of growth of silver nanoparticles in the ion-exchange films has been studied using a combination of (110m)Ag radiotracer, small-angle X-ray scattering (SAXS) experiments, and transmission electron microscopy (TEM). It has been observed that the nanoconfined redox decomposition of silver citrate complex is responsible for the formation of Ag seeds, which thereafter catalyze oxidation of citrate and act as electron sink for subsequent reduction of silver ions. Because of these parallel processes, the particle sizes are in the bimodal distribution at some stages of the reaction. A continuous seeding with parallel growth mechanism has been revealed. Based on the SAXS data and radiotracer kinetics, the growth mechanism has been elucidated as a combination of continuous autoreduction of silver ions on the nanoparticle surfaces and a sudden coalescence of nanoparticles at a critical number density. However, for a fixed period of reduction, the size, size distribution, and number density of thus-formed Ag nanoparticles have been found to be dependent on physical architecture and chemical composition of the matrix.
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Affiliation(s)
- Sabyasachi Patra
- Radiochemistry Division, Bhabha Atomic Research Centre , Trombay, Mumbai 400 085, India
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Patra S, Pandey AK, Sarkar SK, Goswami A. Wonderful nanoconfinement effect on redox reaction equilibrium. RSC Adv 2014. [DOI: 10.1039/c4ra05104a] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Redox reactions have been found to be favoured with nanoscale confinement of solid matrices. Softening of reaction conditions as well as enhancement of reaction kinetics in confined nanospaces has been demonstrated.
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Affiliation(s)
- Sabyasachi Patra
- Radiochemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400 085, India
| | - Ashok K. Pandey
- Radiochemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400 085, India
| | - Sudip K. Sarkar
- GAM Division
- Bhabha Atomic Research Centre
- Mumbai 400 085, India
| | - A. Goswami
- Radiochemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400 085, India
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Tomkins J, Hanna G. Signatures of nanoconfinement on the linear and nonlinear vibrational spectroscopy of a model hydrogen-bonded complex dissolved in a polar solvent. J Phys Chem B 2013; 117:13619-30. [PMID: 24079369 DOI: 10.1021/jp407469f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The one-dimensional IR (1D-IR) absorption and IR pump-probe spectra of a hydrogen stretch in a model hydrogen-bonded complex dissolved in a polar solvent confined in spherical hydrophobic cavities of different sizes were simulated using ground-state mixed quantum-classical dynamics. Due to a thorough analysis of key properties of the complex and solvent from equilibrium trajectory data, we were able to gain insight into the microscopic details underlying the spectra. Both the 1D-IR and IR pump-probe spectra manifested the effects of confinement on the relative stabilities of the covalent and ionic forms of the complex through pronounced changes in their peak intensities and numbers. However, in contrast to the 1D-IR spectra, the time-resolved pump-probe spectra were found to be uniquely sensitive to the changes in the molecular dynamics as the cavity size is varied. In particular, it was found that the variations in the time evolutions of the peak intensities in the pump-probe spectra reflect the differences in the solvation dynamics associated with the various forms of the complex in different locations within the cavities. The ability to detect these differences underscores the advantage of using pump-probe spectroscopy for studying nanoconfined systems.
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Affiliation(s)
- Joseph Tomkins
- Department of Chemistry, University of Alberta , Edmonton, Alberta, Canada T6G 2G2
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Sow CS, Tomkins J, Hanna G. Computational study of the one- and two-dimensional infrared spectra of a proton-transfer mode in a hydrogen-bonded complex dissolved in a polar nanocluster. Chemphyschem 2013; 14:3309-18. [PMID: 23946271 DOI: 10.1002/cphc.201300610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Indexed: 11/07/2022]
Abstract
The signatures of nanosolvation on the one- and two-dimensional (1D and 2D) IR spectra of a proton-transfer mode in a hydrogen-bonded complex dissolved in polar solvent molecule nanoclusters of varying size are elucidated by using mixed quantum-classical molecular dynamics simulations. For this particular system, increasing the number of solvent molecules successively from N=7 to N=9 initiates the transition of the system from a cluster state to a bulk-like state. Both the 1D and 2D IR spectra reflect this transition through pronounced changes in their peak intensities and numbers, but the time-resolved 2D IR spectra also manifest spectral features that uniquely identify the onset of the cluster-to-bulk transition. In particular, it is observed that in the 1D IR spectra, the relative intensities of the peaks change such that the number of peaks decreases from three to two as the size of the cluster increases from N=7 to N=9. In the 2D IR spectra, off-diagonal peaks are observed in the N=7 and N=8 cases at zero waiting time, but not in the N=9 case. It is known that there are no off-diagonal peaks in the 2D IR spectrum of the bulk version of this system at zero waiting time, so the disappearance of these peaks is a unique signature of the onset of bulk-like behavior. Through an examination of the trajectories of various properties of the complex and solvent, it is possible to relate the emergence of these off-diagonal peaks to an interplay between the vibrations of the complex and the solvent polarization dynamics.
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Affiliation(s)
- Chia Shen Sow
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2 (Canada)
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Vartia AA, Thompson WH. Solvation and Spectra of a Charge Transfer Solute in Ethanol Confined within Nanoscale Silica Pores. J Phys Chem B 2012; 116:5414-24. [DOI: 10.1021/jp210737c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anthony A. Vartia
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Ward H. Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
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Ka BJ, Thompson WH. Sampling the Proton Transfer Reaction Coordinate in Mixed Quantum-Classical Molecular Dynamics Simulations. J Phys Chem A 2012; 116:832-8. [DOI: 10.1021/jp206772e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Being J. Ka
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Ward H. Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
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Ghatak C, Rao VG, Ghosh S, Mandal S, Sarkar N. Solvation Dynamics and Rotational Relaxation Study Inside Niosome, A Nonionic Innocuous Poly(ethylene Glycol)-Based Surfactant Assembly: An Excitation Wavelength Dependent Experiment. J Phys Chem B 2011; 115:12514-20. [DOI: 10.1021/jp204473d] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Chiranjib Ghatak
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Vishal Govind Rao
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Shirsendu Ghosh
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Sarthak Mandal
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Nilmoni Sarkar
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
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Abstract
Nanoconfined liquids are of interest because of both their fundamental properties and their potential utility in an array of applications. The structure and dynamics of the liquid can be dramatically impacted by the geometrical constraints and the interactions with the interface. Understanding the molecular-level origins of these changes and how they are determined by the characteristics of the confining framework is the subject of ongoing experimental and theoretical studies. The progress and remaining challenges in these efforts are reviewed in the context of solvation dynamics and proton transfer reactions, processes that are strongly affected by nanoscale confinement.
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Affiliation(s)
- Ward H Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
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Chowdhary J, Ladanyi BM. Molecular simulation study of water mobility in aerosol-OT reverse micelles. J Phys Chem A 2011; 115:6306-16. [PMID: 21548627 DOI: 10.1021/jp201866t] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In this work, we present results from molecular dynamics simulations on the single-molecule relaxation of water within reverse micelles (RMs) of different sizes formed by the surfactant aerosol-OT (AOT, sodium bis(2-ethylhexyl)sulfosuccinate) in isooctane. Results are presented for RM water content w(0) = [H(2)O]/[AOT] in the range from 2.0 to 7.5. We show that translational diffusion of water within the RM can, to a good approximation, be decoupled from the translation of the RM through the isooctane solvent. Water translational mobility within the RM is restricted by the water pool dimensions, and thus, the water mean-squared displacements (MSDs) level off in time. Comparison with models of diffusion in confined geometries shows that a version of the Gaussian confinement model with a biexponential decay of correlations provides a good fit to the MSDs, while a model of free diffusion within a sphere agrees less well with simulation results. We find that the local diffusivity is considerably reduced in the interfacial region, especially as w(0) decreases. Molecular orientational relaxation is monitored by examining the behavior of OH and dipole vectors. For both vectors, orientational relaxation slows down close to the interface and as w(0) decreases. For the OH vector, reorientation is strongly affected by the presence of charged species at the RM interface and these effects are especially pronounced for water molecules hydrogen-bonded to surfactant sites that serve as hydrogen-bond acceptors. For the dipole vector, orientational relaxation near the interface slows down more than that for the OH vector due mainly to the influence of ion-dipole interactions with the sodium counterions. We investigate water OH and dipole reorientation mechanisms by studying the w(0) and interfacial shell dependence of orientational time correlations for different Legendre polynomial orders.
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Affiliation(s)
- Janamejaya Chowdhary
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA
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Sen Mojumdar S, Mondal T, Das AK, Dey S, Bhattacharyya K. Ultrafast and ultraslow proton transfer of pyranine in an ionic liquid microemulsion. J Chem Phys 2010; 132:194505. [DOI: 10.1063/1.3428669] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ka BJ, Thompson WH. Nonadiabatic Effects on Proton Transfer Rate Constants in a Nanoconfined Solvent. J Phys Chem B 2010; 114:7535-42. [DOI: 10.1021/jp911740c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Being J. Ka
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
| | - Ward H. Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
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15
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Dey S, Sasmal DK, Das DK, Bhattacharyya K. A Femtosecond Study of Solvation Dynamics and Anisotropy Decay in a Catanionic Vesicle: Excitation-Wavelength Dependence. Chemphyschem 2008; 9:2848-55. [DOI: 10.1002/cphc.200800658] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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Mitchell-Koch KR, Thompson WH. Infrared spectra of a model phenol-amine proton transfer complex in nanoconfined CH3Cl. J Phys Chem B 2008; 112:7448-59. [PMID: 18517239 DOI: 10.1021/jp076714e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The vibrational spectra of a model phenol-amine proton transfer complex dissolved in CH3Cl solvent confined in a 12 A radius spherical hydrophobic cavity were calculated using mixed quantum-classical molecular dynamics simulations. The reaction free energy of the proton transfer complex was varied in order to explore the contributions to the vibrational absorption band from product and reactant species. The vibrational spectra of the model proton transfer complex resulted in motionally narrowed spectral linewidths with two distinct peaks for products and reactants in cases where the system undergoes chemical exchange. It was found that the n=1 and n=2 vibrational excited states combine to form diabatic states such that the spectra have contributions from both n=0 --> n=1 and n=0 --> n=2 transitions. A strong relationship between the instantaneous vibrational frequency and a collective solvent coordinate was found that assists in understanding the origin of the spectral features.
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Adhikari A, Dey S, Mandal U, Das DK, Ghosh S, Bhattacharyya K. Femtosecond Solvation Dynamics in Different Regions of a Bile Salt Aggregate: Excitation Wavelength Dependence. J Phys Chem B 2008; 112:3575-80. [DOI: 10.1021/jp7106445] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Aniruddha Adhikari
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Shantanu Dey
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Ujjwal Mandal
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Dibyendu Kumar Das
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Subhadip Ghosh
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Kankan Bhattacharyya
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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18
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Kim H, Kapral R. Proton and Deuteron Transfer Reactions in Molecular Nanoclusters. Chemphyschem 2008; 9:470-4. [DOI: 10.1002/cphc.200700709] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ghosh S, Dey S, Mandal U, Adhikari A, Mondal SK, Bhattacharyya K. Ultrafast Proton Transfer of Pyranine in a Supramolecular Assembly: PEO−PPO−PEO Triblock Copolymer and CTAC. J Phys Chem B 2007; 111:13504-10. [DOI: 10.1021/jp072919b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Subhadip Ghosh
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Shantanu Dey
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Ujjwal Mandal
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Aniruddha Adhikari
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Sudip Kumar Mondal
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Kankan Bhattacharyya
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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Mukherjee S, Chowdhury P, Gai F. Tuning the cooperativity of the helix-coil transition by aqueous reverse micelles. J Phys Chem B 2007; 110:11615-9. [PMID: 16800453 DOI: 10.1021/jp062362k] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We show in this letter that the thermodynamic properties of helical peptides can be tuned by varying the degrees of backbone hydration. The latter was achieved by solubilizing peptides in the water pool of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles with different water contents or w0 values. Far-UV circular dichroism measurements on a series of alanine-rich peptides indicate that the helicity of shorter peptides is significantly increased in AOT reverse micelles at low w0 values, as compared to the corresponding helical content in buffer. This result therefore corroborates the previous simulation studies suggesting that desolvation of backbone CO and NH groups increases the stability of monomeric helices. In addition, it was found that the thermal unfolding transition of these peptides can either be very noncooperative or very cooperative, depending on w0 and peptide chain length. A simple model, which considers the heterogeneous distribution of the water molecules inside the polar core of AOT reverse micelles as well as the geometric confinement effect exerted on the peptide by the reverse micelles, was used to interpret these results.
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Kim H, Kapral R. Solvation and proton transfer in polar molecule nanoclusters. J Chem Phys 2006; 125:234309. [PMID: 17190560 DOI: 10.1063/1.2404956] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Proton transfer in a phenol-amine complex dissolved in polar molecule nanoclusters is investigated. The proton transfer rates and mechanisms, as well as the solvation of the complex in the cluster, are studied using both adiabatic and nonadiabatic dynamics. The phenol-amine complex exists in ionic and covalent forms and as the size of the cluster increases the ionic form gains stability at the expense of the covalent form. Both the adiabatic and nonadiabatic transfer reaction rates increase with cluster size. Given a fixed cluster size, the stability of the covalent state increases with increasing temperature. The proton transfer rates do not change monotonously with an increase in temperature. A strong correlation between the solvent polarization reaction coordinate and the location of the phenol-amine complex in the cluster is found. The ionic form of the complex strongly prefers the interior of the cluster while the covalent form prefers to lie on the cluster surface.
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Affiliation(s)
- Hyojoon Kim
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
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Kim H, Hanna G, Kapral R. Analysis of kinetic isotope effects for nonadiabatic reactions. J Chem Phys 2006; 125:084509. [PMID: 16965031 DOI: 10.1063/1.2336778] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Factors influencing the rates of quantum mechanical particle transfer reactions in many-body systems are discussed. The investigations are carried out on a simple model for a proton transfer reaction that captures generic features seen in more realistic models of condensed phase systems. The model involves a bistable quantum oscillator coupled to a one-dimensional double-well reaction coordinate, which is in turn coupled to a bath of harmonic oscillators. Reactive-flux correlation functions that involve quantum-classical Liouville dynamics for chemical species operators and quantum equilibrium sampling are used to estimate the reaction rates. Approximate analytical expressions for the quantum equilibrium structure are derived. Reaction rates are shown to be influenced significantly by both the quantum equilibrium structure and nonadiabatic dynamics. Nonadiabatic dynamical effects are found to play the major role in determining the magnitude of the kinetic isotope effect for the model transfer reaction.
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Affiliation(s)
- Hyojoon Kim
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
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