Isotopic equilibria in aqueous clusters at low temperatures: Insights from the MB-pol many-body potential

By combining path-integrals molecular dynamics simulations with the accurate MB-pol potential energy surface, we investigate the role of alternative potential models on isotopic fractionation ratios between H and D atoms at dangling positions in water clusters at low temperatures. Our results show c...

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Detalles Bibliográficos
Publicado: 2018
Materias:
Free energy
Hydrogen bonds
Kinetic energy
Molecular dynamics
Molecular physics
Potential energy
Potential energy surfaces
Quantum chemistry
Rate constants
Stabilization
Free-energy difference
Isotopic fractionations
Low temperatures
Many-body potentials
Measured results
Molecular dynamics simulations
Orthogonal directions
Potential Model
Isotopes
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v148_n8_p_Videla
http://hdl.handle.net/20.500.12110/paper_00219606_v148_n8_p_Videla
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00219606_v148_n8_p_Videla
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spelling paper:paper_00219606_v148_n8_p_Videla2023-06-08T14:44:30Z Isotopic equilibria in aqueous clusters at low temperatures: Insights from the MB-pol many-body potential Free energy Hydrogen bonds Kinetic energy Molecular dynamics Molecular physics Potential energy Potential energy surfaces Quantum chemistry Rate constants Stabilization Free-energy difference Isotopic fractionations Low temperatures Many-body potentials Measured results Molecular dynamics simulations Orthogonal directions Potential Model Isotopes By combining path-integrals molecular dynamics simulations with the accurate MB-pol potential energy surface, we investigate the role of alternative potential models on isotopic fractionation ratios between H and D atoms at dangling positions in water clusters at low temperatures. Our results show clear stabilizations of the lighter isotope at dangling sites, characterized by free energy differences ΔG that become comparable to or larger than kBT for temperatures below ∼75 K. The comparison between these results to those previously reported using the empirical q-TIP4P/F water model [P. E. Videla et al., J. Phys. Chem. Lett. 5, 2375 (2014)] reveals that the latter Hamiltonian overestimates the H stabilization by ∼25%. Moreover, predictions from the MB-pol model are in much better agreement with measured results reported for similar isotope equilibria at ice surfaces. The dissection of the quantum kinetic energies into orthogonal directions shows that the dominant differences between the two models are to be found in the anharmonic characteristics of the potential energy surfaces along OH bond directions involved in hydrogen bonds. © 2018 Author(s). 2018 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v148_n8_p_Videla http://hdl.handle.net/20.500.12110/paper_00219606_v148_n8_p_Videla
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Free energy
Hydrogen bonds
Kinetic energy
Molecular dynamics
Molecular physics
Potential energy
Potential energy surfaces
Quantum chemistry
Rate constants
Stabilization
Free-energy difference
Isotopic fractionations
Low temperatures
Many-body potentials
Measured results
Molecular dynamics simulations
Orthogonal directions
Potential Model
Isotopes
spellingShingle Free energy
Hydrogen bonds
Kinetic energy
Molecular dynamics
Molecular physics
Potential energy
Potential energy surfaces
Quantum chemistry
Rate constants
Stabilization
Free-energy difference
Isotopic fractionations
Low temperatures
Many-body potentials
Measured results
Molecular dynamics simulations
Orthogonal directions
Potential Model
Isotopes
Isotopic equilibria in aqueous clusters at low temperatures: Insights from the MB-pol many-body potential
topic_facet Free energy
Hydrogen bonds
Kinetic energy
Molecular dynamics
Molecular physics
Potential energy
Potential energy surfaces
Quantum chemistry
Rate constants
Stabilization
Free-energy difference
Isotopic fractionations
Low temperatures
Many-body potentials
Measured results
Molecular dynamics simulations
Orthogonal directions
Potential Model
Isotopes
description By combining path-integrals molecular dynamics simulations with the accurate MB-pol potential energy surface, we investigate the role of alternative potential models on isotopic fractionation ratios between H and D atoms at dangling positions in water clusters at low temperatures. Our results show clear stabilizations of the lighter isotope at dangling sites, characterized by free energy differences ΔG that become comparable to or larger than kBT for temperatures below ∼75 K. The comparison between these results to those previously reported using the empirical q-TIP4P/F water model [P. E. Videla et al., J. Phys. Chem. Lett. 5, 2375 (2014)] reveals that the latter Hamiltonian overestimates the H stabilization by ∼25%. Moreover, predictions from the MB-pol model are in much better agreement with measured results reported for similar isotope equilibria at ice surfaces. The dissection of the quantum kinetic energies into orthogonal directions shows that the dominant differences between the two models are to be found in the anharmonic characteristics of the potential energy surfaces along OH bond directions involved in hydrogen bonds. © 2018 Author(s).
title Isotopic equilibria in aqueous clusters at low temperatures: Insights from the MB-pol many-body potential
title_short Isotopic equilibria in aqueous clusters at low temperatures: Insights from the MB-pol many-body potential
title_full Isotopic equilibria in aqueous clusters at low temperatures: Insights from the MB-pol many-body potential
title_fullStr Isotopic equilibria in aqueous clusters at low temperatures: Insights from the MB-pol many-body potential
title_full_unstemmed Isotopic equilibria in aqueous clusters at low temperatures: Insights from the MB-pol many-body potential
title_sort isotopic equilibria in aqueous clusters at low temperatures: insights from the mb-pol many-body potential
publishDate 2018
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v148_n8_p_Videla
http://hdl.handle.net/20.500.12110/paper_00219606_v148_n8_p_Videla
_version_ 1768541877445853184

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