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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todo:paper_00219606_v148_n8_p_Videla2023-10-03T14:24:39Z Isotopic equilibria in aqueous clusters at low temperatures: Insights from the MB-pol many-body potential Videla, P.E. Rossky, P.J. Laria, D. 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). JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar 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 |
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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 Videla, P.E. Rossky, P.J. Laria, D. 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). |
format |
JOUR |
author |
Videla, P.E. Rossky, P.J. Laria, D. |
author_facet |
Videla, P.E. Rossky, P.J. Laria, D. |
author_sort |
Videla, P.E. |
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 |
url |
http://hdl.handle.net/20.500.12110/paper_00219606_v148_n8_p_Videla |
work_keys_str_mv |
AT videlape isotopicequilibriainaqueousclustersatlowtemperaturesinsightsfromthembpolmanybodypotential AT rosskypj isotopicequilibriainaqueousclustersatlowtemperaturesinsightsfromthembpolmanybodypotential AT lariad isotopicequilibriainaqueousclustersatlowtemperaturesinsightsfromthembpolmanybodypotential |
_version_ |
1782028179212337152 |