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Yadav VK. Vibrational spectral diffusion in supercritical deuterated ammonia from first principles simulations: Roles of hydrogen bonds, free ND modes and inertial rotation of ammonia molecules. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.08.089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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2
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Yadav VK, Chandra A. Dynamics of vibrational frequency fluctuations in deuterated liquid ammonia: roles of fluctuating hydrogen bonds and free ND modes. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1475739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Vivek Kumar Yadav
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur, India
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur, India
- Department of Theoretical and Computational Molecular Science, Institute of Molecular Science , Okazaki, Japan
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3
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Synthesis of K2Se solar cell dopant in liquid NH3 by solvated electron transfer to elemental selenium. Electrochem commun 2018. [DOI: 10.1016/j.elecom.2018.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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4
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Sun WM, Wu D, Li Y, Li ZR. Theoretical study on superalkali (Li3) in ammonia: novel alkalides with considerably large first hyperpolarizabilities. Dalton Trans 2014; 43:486-94. [DOI: 10.1039/c3dt51559a] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Lodge MTJH, Cullen P, Rees NH, Spencer N, Maeda K, Harmer JR, Jones MO, Edwards PP. Multielement NMR Studies of the Liquid–Liquid Phase Separation and the Metal-to-Nonmetal Transition in Fluid Lithium– and Sodium–Ammonia Solutions. J Phys Chem B 2013; 117:13322-34. [DOI: 10.1021/jp404023j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matthew T. J. H. Lodge
- Department
of Chemistry, Centre for Advanced Electron Spin Resonance (CAESR),
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - P. Cullen
- Department
of Chemistry, Centre for Advanced Electron Spin Resonance (CAESR),
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Nicholas H. Rees
- Department
of Chemistry, Centre for Advanced Electron Spin Resonance (CAESR),
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Neil Spencer
- School
of Chemistry, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, U.K
| | - Kiminori Maeda
- Department
of Chemistry, Centre for Advanced Electron Spin Resonance (CAESR),
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Jeffrey R. Harmer
- Department
of Chemistry, Centre for Advanced Electron Spin Resonance (CAESR),
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
- Centre
for Advanced Imaging, University of Queensland, St Lucia, QLD, 4072, Australia
| | - Martin O. Jones
- Department
of Chemistry, Centre for Advanced Electron Spin Resonance (CAESR),
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Peter P. Edwards
- Department
of Chemistry, Centre for Advanced Electron Spin Resonance (CAESR),
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
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6
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Orabi EA, Lamoureux G. Molecular Dynamics Investigation of Alkali Metal Ions in Liquid and Aqueous Ammonia. J Chem Theory Comput 2013; 9:2324-38. [DOI: 10.1021/ct4001069] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Esam A. Orabi
- Department of Chemistry
and Biochemistry and Centre
for Research in Molecular Modeling (CERMM), Concordia University,
7141 Sherbrooke Street West, Montréal, Québec H4B 1R6,
Canada
| | - Guillaume Lamoureux
- Department of Chemistry
and Biochemistry and Centre
for Research in Molecular Modeling (CERMM), Concordia University,
7141 Sherbrooke Street West, Montréal, Québec H4B 1R6,
Canada
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7
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Maeda K, Lodge MT, Harmer J, Freed JH, Edwards PP. Electron tunneling in lithium-ammonia solutions probed by frequency-dependent electron spin relaxation studies. J Am Chem Soc 2012; 134:9209-18. [PMID: 22568866 PMCID: PMC3415590 DOI: 10.1021/ja212015b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Electron transfer or quantum tunneling dynamics for excess or solvated electrons in dilute lithium-ammonia solutions have been studied by pulse electron paramagnetic resonance (EPR) spectroscopy at both X- (9.7 GHz) and W-band (94 GHz) frequencies. The electron spin-lattice (T(1)) and spin-spin (T(2)) relaxation data indicate an extremely fast transfer or quantum tunneling rate of the solvated electron in these solutions which serves to modulate the hyperfine (Fermi-contact) interaction with nitrogen nuclei in the solvation shells of ammonia molecules surrounding the localized, solvated electron. The donor and acceptor states of the solvated electron in these solutions are the initial and final electron solvation sites found before, and after, the transfer or tunneling process. To interpret and model our electron spin relaxation data from the two observation EPR frequencies requires a consideration of a multiexponential correlation function. The electron transfer or tunneling process that we monitor through the correlation time of the nitrogen Fermi-contact interaction has a time scale of (1-10) × 10(-12) s over a temperature range 230-290 K in our most dilute solution of lithium in ammonia. Two types of electron-solvent interaction mechanisms are proposed to account for our experimental findings. The dominant electron spin relaxation mechanism results from an electron tunneling process characterized by a variable donor-acceptor distance or range (consistent with such a rapidly fluctuating liquid structure) in which the solvent shell that ultimately accepts the transferring electron is formed from random, thermal fluctuations of the liquid structure in, and around, a natural hole or Bjerrum-like defect vacancy in the liquid. Following transfer and capture of the tunneling electron, further solvent-cage relaxation with a time scale of ∼10(-13) s results in a minor contribution to the electron spin relaxation times. This investigation illustrates the great potential of multifrequency EPR measurements to interrogate the microscopic nature and dynamics of ultrafast electron transfer or quantum-tunneling processes in liquids. Our results also impact on the universal issue of the role of a host solvent (or host matrix, e.g. a semiconductor) in mediating long-range electron transfer processes and we discuss the implications of our results with a range of other materials and systems exhibiting the phenomenon of electron transfer.
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Affiliation(s)
- Kiminori Maeda
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Matthew T.J. Lodge
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Jeffrey Harmer
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Jack H. Freed
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca NY 14853-1301, USA
| | - Peter P. Edwards
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
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Zhang H, Liu ZF. The solvation of two electrons in the gaseous clusters of Na−(NH3)nand Li−(NH3)n. J Chem Phys 2012; 136:124314. [DOI: 10.1063/1.3697968] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Chakraborty D, Chandra A. Voids and necks in liquid ammonia and their roles in diffusion of ions of varying size. J Comput Chem 2012; 33:843-52. [DOI: 10.1002/jcc.22910] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 10/30/2011] [Accepted: 11/20/2011] [Indexed: 11/05/2022]
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11
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Zurek E. Alkali metals in ethylenediamine: a computational study of the optical absorption spectra and NMR parameters of [M(en)3(δ+)·M(δ-)] ion pairs. J Am Chem Soc 2011; 133:4829-39. [PMID: 21366240 DOI: 10.1021/ja1085244] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The optical absorption spectra of alkali metals in ethylenediamine have provided evidence for a third oxidation state, -1, of all of the alkali metals heavier than lithium. Experimentally determined NMR parameters have supported this interpretation, further indicating that whereas Na(-) is a genuine metal anion, the interaction of the alkali anion with the medium becomes progressively stronger for the larger metals. Herein, first-principles computations based upon density functional theory are carried out on various species which may be present in solutions composed of alkali metals and ethylenediamine. The energies of a number of hypothetical reactions computed with a continuum solvation model indicate that neither free metal anions, M(-), nor solvated electrons are the most stable species. Instead, [Li(en)(3)](2) and [M(en)(3)(δ+)·M(δ-)] (M = Na, K, Rb, Cs) are predicted to have enhanced stability. The M(en)(3) complexes can be viewed as superalkalis or expanded alkalis, ones in which the valence electron density is pulled out to a greater extent than in the alkali metals alone. The computed optical absorption spectra and NMR parameters of the [Li(en)(3)](2) superalkali dimer and the [M(en)(3)(δ+)·M(δ-)] superalkali-alkali mixed dimers are in good agreement with the aforementioned experimental results, providing further evidence that these may be the dominant species in solution. The latter can also be thought of as an ion pair formed from an alkali metal anion (M(-)) and solvated cation (M(en)(3)(+)).
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Affiliation(s)
- Eva Zurek
- Department of Chemistry, State University of New York at Buffalo, 331 Natural Sciences Complex, Buffalo, New York 14260, USA.
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12
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Pratihar S, Chandra A. A first principles molecular dynamics study of excess electron and lithium atom solvation in water-ammonia mixed clusters: structural, spectral, and dynamical behaviors of [(H2O)5NH3]- and Li(H2O)5NH3 at finite temperature. J Chem Phys 2011; 134:034302. [PMID: 21261348 DOI: 10.1063/1.3511701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
First principles molecular dynamics simulations are carried out to investigate the solvation of an excess electron and a lithium atom in mixed water-ammonia cluster (H(2)O)(5)NH(3) at a finite temperature of 150 K. Both [(H(2)O)(5)NH(3)](-) and Li(H(2)O)(5)NH(3) clusters are seen to display substantial hydrogen bond dynamics due to thermal motion leading to many different isomeric structures. Also, the structures of these two clusters are found to be very different from each other and also very different from the corresponding neutral cluster without any excess electron or the metal atom. Spontaneous ionization of Li atom occurs in the case of Li(H(2)O)(5)NH(3). The spatial distribution of the singly occupied molecular orbital shows where and how the excess (or free) electron is primarily localized in these clusters. The populations of single acceptor (A), double acceptor (AA), and free (NIL) type water and ammonia molecules are found to be significantly high. The dangling hydrogens of these type of water or ammonia molecules are found to primarily capture the free electron. It is also found that the free electron binding motifs evolve with time due to thermal fluctuations and the vertical detachment energy of [(H(2)O)(5)NH(3)](-) and vertical ionization energy of Li(H(2)O)(5)NH(3) also change with time along the simulation trajectories. Assignments of the observed peaks in the vibrational power spectra are done and we found a one to one correlation between the time-averaged populations of water and ammonia molecules at different H-bonding sites with the various peaks of power spectra. The frequency-time correlation functions of OH stretch vibrational frequencies of these clusters are also calculated and their decay profiles are analyzed in terms of the dynamics of hydrogen bonded and dangling OH modes. It is found that the hydrogen bond lifetimes in these clusters are almost five to six times longer than that of pure liquid water at room temperature.
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Affiliation(s)
- Subha Pratihar
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
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Pratihar S, Chandra A. A first principles molecular dynamics study of lithium atom solvation in binary liquid mixture of water and ammonia: Structural, electronic, and dynamical properties. J Chem Phys 2011; 134:024519. [DOI: 10.1063/1.3511702] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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14
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Pratihar S, Chandra A. Excess electron and lithium atom solvation in water clusters at finite temperature: an ab initio molecular dynamics study of the structural, spectral, and dynamical behavior of (H2O)6- and Li(H2O)6. J Phys Chem A 2010; 114:11869-78. [PMID: 20958010 DOI: 10.1021/jp103139c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The roles of hydrogen bonds in the solvation of an excess electron and a lithium atom in water hexamer cluster at 150 K have been studied by means of ab initio molecular dynamics simulations. It is found that the hydrogen bonded structures of (H(2)O)(6)(-) and Li(H(2)O)(6) clusters are very different from each other and they dynamically evolve from one conformer to other along their simulation trajectories. The populations of the single acceptor, double acceptor, and free type water molecules are found to be significantly high unlike that in pure water clusters. Free hydrogens of these type of water molecules primarily capture the unbound electron density in these clusters. It is found that the binding motifs of the free electron evolve with time and the vertical detachment energy of (H(2)O)(6)(-) and vertical ionization energy of Li(H(2)O)(6) also change with time. Assignments of the observed peaks in vibrational power spectra are done, and we found direct correlations between the time-averaged population of water molecules in different hydrogen bonding states and the spectral features. The dynamical aspects of these clusters have also been studied through calculations of time correlations of instantaneous stretch frequencies of OH modes which are obtained from the simulation trajectories through a time series analysis.
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Affiliation(s)
- Subha Pratihar
- Department of Chemistry, Indian Institute of Technology, Kanpur, India 208016
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Abstract
Using the path integral centroid approach, we investigate dispersion interactions between electrons solvated in metal-ammonia solutions. We have argued that at finite metal concentrations, the behavior of the solvated electrons is controlled by these interactions. The latter result in a peculiar nonmetal-metal transition, which appears as a sharp dielectric enhancement and a mechanical instability of the system. Our results indicate also that the solvated electrons are to be considered as a two-component mixture consisting of localized and delocalized electrons beyond the critical density corresponding to this mechanical instability.
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Affiliation(s)
- Gennady N Chuev
- Max Planck Institute for Mathematics in the Sciences, Inselstrasse 22, Leipzig 04103, Germany.
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Chiesa M, Giamello E, Van Doorslaer S. Ammoniated electrons stabilized at the surface of MgO. J Am Chem Soc 2009; 131:12664-70. [PMID: 19673518 DOI: 10.1021/ja903179b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The reaction of excess electrons at the surface of MgO with ammonia leads to surface ammoniated electrons analogous to those formed when alkali metals are dissolved in anhydrous ammonia. Surface excess electrons are found to be solvated by up to three ammonia molecules, and well-resolved CW and pulsed EPR spectra allow for a precise description of the unpaired electron spin density distribution over the solvent molecules. The large majority of the electron spin density resides in the first-shell nitrogen fragments. HYSCORE spectra allow obtaining for the first time the full hyperfine interaction of the solvated electron with the ammonia protons, which is consistent with a small and negative spin density in the (1)H 1s orbital. Furthermore, the hyperfine and nuclear quadrupole tenors of the second-shell nitrogens could be unravelled.
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Affiliation(s)
- Mario Chiesa
- Dipartimento di Chimica IFM, Università di Torino and NIS, Nanostructured Interfaces and Surfaces Centre of Excellence, Via P. Giuria 7, I - 10125 Torino, Italy.
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Zurek E, Edwards P, Hoffmann R. Lithium-Ammoniak-Lösungen: eine molekulare Betrachtung. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200900373] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Zurek E, Edwards P, Hoffmann R. A Molecular Perspective on Lithium-Ammonia Solutions. Angew Chem Int Ed Engl 2009; 48:8198-232. [DOI: 10.1002/anie.200900373] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Pratihar S, Chandra A. Microscopic solvation of a lithium atom in water-ammonia mixed clusters: Solvent coordination and electron localization in presence of a counterion. J Chem Phys 2008; 129:024511. [DOI: 10.1063/1.2951989] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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