skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Switching off hydrogen-bond-driven excitation modes in liquid methanol

Abstract

Hydrogen bonding plays an essential role on intermolecular forces, and consequently on the thermodynamics of materials defined by this elusive bonding character. It determines the property of a vital liquid as water as well as many processes crucial for life. The longstanding controversy on the nature of the hydrogen bond (HB) can be settled by looking at the effect of a vanishing HB interaction on the microscopic properties of a given hydrogen-bonded fluid. This task suits the capabilities of computer simulations techniques, which allow to easily switch off HB interactions. We then use molecular dynamics to study the microscopic properties of methanol, a prototypical HB liquid. Fundamental aspects of the dynamics of methanol at room temperature were contextualised only very recently and its rich dynamics was found to have striking analogies with that of water. The lower temperature (200 K) considered in the present study led us to observe that the molecular centre-of-mass dynamics is dominated by four modes. Most importantly, the computational ability to switch on and off hydrogen bonds permitted us to identify which, among these modes, have a pure HB-origin. This clarifies the role of hydrogen bonds in liquid dynamics, disclosing new research opportunities and unexplored interpretationmore » schemes.« less

Authors:
 [1];  [2];  [1];  [3];  [4]; ORCiD logo [5];  [6]
  1. Consiglio Nazionale delle Ricerche (CNR), Sesto Fiorentino (Italy). Istituto dei Sistemi Complessi
  2. Institut Laue Langevin, Grenoble, (France)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
  4. Consiglio Nazionale delle Ricerche (CNR), Grenoble (France). Istituto Officina dei materiali
  5. Istituto Italiano di Tecnologia, Roma (Italy). Center for Life Nano Science
  6. Univ. di Firenze, Sesto Fiorentino (Italy). Dipartimento di Fisica e Astronomia
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1413924
Report Number(s):
BNL-114439-2017-JA
Journal ID: ISSN 2045-2322
Grant/Contract Number:
SC0012704
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Chemical physics

Citation Formats

Bellissima, Stefano, González, Miguel A., Bafile, Ubaldo, Cunsolo, Alessandro, Formisano, Ferdinando, De Panfilis, Simone, and Guarini, Eleonora. Switching off hydrogen-bond-driven excitation modes in liquid methanol. United States: N. p., 2017. Web. doi:10.1038/s41598-017-10259-4.
Bellissima, Stefano, González, Miguel A., Bafile, Ubaldo, Cunsolo, Alessandro, Formisano, Ferdinando, De Panfilis, Simone, & Guarini, Eleonora. Switching off hydrogen-bond-driven excitation modes in liquid methanol. United States. doi:10.1038/s41598-017-10259-4.
Bellissima, Stefano, González, Miguel A., Bafile, Ubaldo, Cunsolo, Alessandro, Formisano, Ferdinando, De Panfilis, Simone, and Guarini, Eleonora. 2017. "Switching off hydrogen-bond-driven excitation modes in liquid methanol". United States. doi:10.1038/s41598-017-10259-4. https://www.osti.gov/servlets/purl/1413924.
@article{osti_1413924,
title = {Switching off hydrogen-bond-driven excitation modes in liquid methanol},
author = {Bellissima, Stefano and González, Miguel A. and Bafile, Ubaldo and Cunsolo, Alessandro and Formisano, Ferdinando and De Panfilis, Simone and Guarini, Eleonora},
abstractNote = {Hydrogen bonding plays an essential role on intermolecular forces, and consequently on the thermodynamics of materials defined by this elusive bonding character. It determines the property of a vital liquid as water as well as many processes crucial for life. The longstanding controversy on the nature of the hydrogen bond (HB) can be settled by looking at the effect of a vanishing HB interaction on the microscopic properties of a given hydrogen-bonded fluid. This task suits the capabilities of computer simulations techniques, which allow to easily switch off HB interactions. We then use molecular dynamics to study the microscopic properties of methanol, a prototypical HB liquid. Fundamental aspects of the dynamics of methanol at room temperature were contextualised only very recently and its rich dynamics was found to have striking analogies with that of water. The lower temperature (200 K) considered in the present study led us to observe that the molecular centre-of-mass dynamics is dominated by four modes. Most importantly, the computational ability to switch on and off hydrogen bonds permitted us to identify which, among these modes, have a pure HB-origin. This clarifies the role of hydrogen bonds in liquid dynamics, disclosing new research opportunities and unexplored interpretation schemes.},
doi = {10.1038/s41598-017-10259-4},
journal = {Scientific Reports},
number = 1,
volume = 7,
place = {United States},
year = 2017,
month = 8
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:
  • The hydrogen bond structure of liquid methanol was investigated as a function of pressure and temperature up to 2.8 kbar and from 297 to 413 K. Chemical shifts of the CH{sub 3} and OH groups were monitored throughout this pressure and temperature regime, and the chemical shift difference between these two groups was used to describe changes of the hydrogen bond network in methanol. The hydrogen bond equilibrium was investigated using molecular dynamics simulations and a phenomenological model describing clustering in liquid methanol. Results are presented concerning the size and distribution of hydrogen-bonded clusters in methanol as a function ofmore » pressure and temperature. The results indicate that the extent of hydrogen bonding decreases upon an increase in temperature. The results for pressure are equivocal. The phenomenological model suggests that hydrogen bonding decreases with increasing pressure, which supports earlier interpretations regarding the measured self-diffusion coefficients in deuterated methanol as a function of pressure. The molecular dynamics simulations, however, show an increase in hydrogen bonding with increasing pressure. 26 refs., 5 figs., 5 tabs.« less
  • The proton spin-lattice relaxation times and proton chemical shifts for the hydroxyl and methyl protons in methanol were measured at liquid and supercritical densities using capillary high-pressure NMR spectroscopy. The pressure range for the proton nuclear relaxation measurements was between 50 and 3500 bar over a temperature range of 50--3500 bar and a temperature range of 298--773 K. Attempts were made to separate the contributions of the dipolar and spin-rotation interactions to the spin-relaxation processes at each thermodynamic condition over methanol densities ranging from liquid to supercritical fluid. An average number of hydrogen bonds per molecule in methanol and themore » apparent activation energy of the methyl group internal rotation have been extracted from the experimental relaxation data. The extracted quantities show a moderate pressure dependence in addition to temperature effects, which suggest that molecular packing effects on hydrogen-bonded methanol are important at higher pressures. A comparison between methanol and water at similar thermodynamic conditions was also made to obtain new insight into these two important supercritical solvents.« less
  • The relatively simple molecular structure of hydrogen-bonded (HB) systems is often belied by their exceptionally complex thermodynamic and microscopic behaviour. For this reason, after a thorough experimental, computational and theoretical scrutiny, the dynamics of molecules in HB systems still eludes a comprehensive understanding. Aiming at shedding some insight into this topic, we jointly used neutron Brillouin scattering and molecular dynamics simulations to probe the dynamics of a prototypical hydrogen-bonded alcohol, liquid methanol. The comparison with the most thoroughly investigated HB system, liquid water, pinpoints common behaviours of their THz microscopic dynamics, thereby providing additional information on the role of HBmore » dynamics in these two systems. This study demonstrates that the dynamic behaviour of methanol is much richer than what so far known, and prompts us to establish striking analogies with the features of liquid and supercooled water. In particular, based on the strong differences between the structural properties of the two systems, our results suggest that the assignment of some dynamical properties to the tetrahedral character of water structure should be questioned. We finally highlight the similarities between the characteristic decay times of the time correlation function, as obtained from our data and the mean lifetime of hydrogen bond known in literature.« less
  • The discrepancy between experimental and harmonically predicted shifts of the OH stretching fundamental of methanol upon hydrogen bonding to a second methanol unit is too large to be blamed mostly on diagonal and off-diagonal anharmonicity corrections. It is shown that a decisive contribution comes from post-MP2 electron correlation effects, which appear not to be captured by any of the popular density functionals. We also identify that the major deficiency is in the description of the donor OH bond. Together with estimates for the electronic and harmonically zero-point corrected dimer binding energies, this work provides essential constraints for a quantitative descriptionmore » of this simple hydrogen bond. The spectroscopic dissociation energy is predicted to be larger than 18 kJ/mol and the harmonic OH-stretching fundamental shifts by about −121 cm{sup −1} upon dimerization, somewhat more than in the anharmonic experiment (−111 cm{sup −1})« less