Surface isotope segregation as a probe of temperature in water nanoclusters
Using ring polymer molecular dynamics simulations, we examine equilibrium and dynamical characteristics of solid-like, aqueous clusters that combine isotopic mixtures of HDO dilute in H2O, at temperatures intermediate between 50 and 175 K. In particular, we focus attention on the relative thermodyna...
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2014
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_19487185_v5_n13_p2375_Videla http://hdl.handle.net/20.500.12110/paper_19487185_v5_n13_p2375_Videla |
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paper:paper_19487185_v5_n13_p2375_Videla2023-06-08T16:32:33Z Surface isotope segregation as a probe of temperature in water nanoclusters Videla, Pablo Ernesto Laria, Daniel Hector isotope effects nuclear quantum fluctuations path integrals ring polymer molecular dynamics Free energy Hydrogen bonds Molecular dynamics Quantum electronics Surface segregation Dynamical characteristics Free-energy difference Isotope effect Molecular dynamics simulations Path integral Quantum fluctuation Ring polymers Water nanoclusters Isotopes Using ring polymer molecular dynamics simulations, we examine equilibrium and dynamical characteristics of solid-like, aqueous clusters that combine isotopic mixtures of HDO dilute in H2O, at temperatures intermediate between 50 and 175 K. In particular, we focus attention on the relative thermodynamic stabilities of the two isotopes at dangling hydrogen bond sites. The water octamer is analyzed as a reference system. For this aggregate, decreasing temperature yields a gradual stabilization of the light isotope at dangling sites in molecules acting as single-donor-double-acceptors of hydrogen bonds. At T ∼ 50 K, the imbalance between the corresponding quantum kinetic energies leads to a free energy difference between dangling and hydrogen bonded sites of the order of ∼2kBT. Similar free energy differences were found at dangling sites in Nw = 50 water clusters. The extent of the H/D segregation can be adequately monitored by modifications in the peak intensity of the high frequency shoulder of the stretching band of the infrared spectrum. These signals, in turn, represent a potential experimental signature of the elusive temperature of clusters in molecular beams. © 2014 American Chemical Society. Fil:Videla, P.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Laria, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2014 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_19487185_v5_n13_p2375_Videla http://hdl.handle.net/20.500.12110/paper_19487185_v5_n13_p2375_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 |
isotope effects nuclear quantum fluctuations path integrals ring polymer molecular dynamics Free energy Hydrogen bonds Molecular dynamics Quantum electronics Surface segregation Dynamical characteristics Free-energy difference Isotope effect Molecular dynamics simulations Path integral Quantum fluctuation Ring polymers Water nanoclusters Isotopes |
| spellingShingle |
isotope effects nuclear quantum fluctuations path integrals ring polymer molecular dynamics Free energy Hydrogen bonds Molecular dynamics Quantum electronics Surface segregation Dynamical characteristics Free-energy difference Isotope effect Molecular dynamics simulations Path integral Quantum fluctuation Ring polymers Water nanoclusters Isotopes Videla, Pablo Ernesto Laria, Daniel Hector Surface isotope segregation as a probe of temperature in water nanoclusters |
| topic_facet |
isotope effects nuclear quantum fluctuations path integrals ring polymer molecular dynamics Free energy Hydrogen bonds Molecular dynamics Quantum electronics Surface segregation Dynamical characteristics Free-energy difference Isotope effect Molecular dynamics simulations Path integral Quantum fluctuation Ring polymers Water nanoclusters Isotopes |
| description |
Using ring polymer molecular dynamics simulations, we examine equilibrium and dynamical characteristics of solid-like, aqueous clusters that combine isotopic mixtures of HDO dilute in H2O, at temperatures intermediate between 50 and 175 K. In particular, we focus attention on the relative thermodynamic stabilities of the two isotopes at dangling hydrogen bond sites. The water octamer is analyzed as a reference system. For this aggregate, decreasing temperature yields a gradual stabilization of the light isotope at dangling sites in molecules acting as single-donor-double-acceptors of hydrogen bonds. At T ∼ 50 K, the imbalance between the corresponding quantum kinetic energies leads to a free energy difference between dangling and hydrogen bonded sites of the order of ∼2kBT. Similar free energy differences were found at dangling sites in Nw = 50 water clusters. The extent of the H/D segregation can be adequately monitored by modifications in the peak intensity of the high frequency shoulder of the stretching band of the infrared spectrum. These signals, in turn, represent a potential experimental signature of the elusive temperature of clusters in molecular beams. © 2014 American Chemical Society. |
| author |
Videla, Pablo Ernesto Laria, Daniel Hector |
| author_facet |
Videla, Pablo Ernesto Laria, Daniel Hector |
| author_sort |
Videla, Pablo Ernesto |
| title |
Surface isotope segregation as a probe of temperature in water nanoclusters |
| title_short |
Surface isotope segregation as a probe of temperature in water nanoclusters |
| title_full |
Surface isotope segregation as a probe of temperature in water nanoclusters |
| title_fullStr |
Surface isotope segregation as a probe of temperature in water nanoclusters |
| title_full_unstemmed |
Surface isotope segregation as a probe of temperature in water nanoclusters |
| title_sort |
surface isotope segregation as a probe of temperature in water nanoclusters |
| publishDate |
2014 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_19487185_v5_n13_p2375_Videla http://hdl.handle.net/20.500.12110/paper_19487185_v5_n13_p2375_Videla |
| work_keys_str_mv |
AT videlapabloernesto surfaceisotopesegregationasaprobeoftemperatureinwaternanoclusters AT lariadanielhector surfaceisotopesegregationasaprobeoftemperatureinwaternanoclusters |
| _version_ |
1768541820265955328 |